Publications by authors named "Bas J"

We report a case of Whipple disease involving the brain, optic chiasm, posterior fossa, and spinal cord. We evaluate the role of MR imaging for initial evaluation and for long-term follow-up of Whipple disease involving the CNS. We also discuss the semiologic characteristics of the lesions.

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To assess the involvement of the immune system in Parkinson's disease we studied the phenotype of circulating lymphocytes in 30 untreated and 34 treated patients. We found a numeric decrease in helper T cells (higher in CD4(+)CD45RA(+) than in CD4(+)CD29(+)) and B cells, and a rise in activated, CD4(+)CD25(+) lymphocytes that was correlated with lymphocyte depletion. All these alterations were independent of levodopa treatment.

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For the diagnosis of rheumatoid vasculitis (RV), histological examination of a blindly-taken muscle biopsy is advocated. If fibrinoid necrosis (FN) is observed in one or more tissue sections of the biopsy the diagnosis of RV is confirmed. The diagnostic value of such histological investigation depends on the prevalence of FN in biopsies of RV patients, the number of tissue sections that are investigated, and the sampling design with which the tissue sections are obtained from the biopsy.

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Deep brain stimulation by high frequency (HFS) has been developed starting in the thalamic target (Vim) from pragmatic observations and subsequently followed by other targets, such as the subthalamic nucleus (STN) and pallidum as an application of current knowledge from basic preclinical research in neuroscience. The mechanism involved by this neurosurgical approach is not completely solved. For Vim we have formed the hypothesis that HFS induces a jamming of sensory-motor loops but for the STN, from our experimental research in rats we have shown that HFS induces functional inhibition of cell activity in the target nuclei.

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The first operation of the European Synchrotron Radiation Facility (ESRF) medical beamline is reported in this paper. The goal of the angiography project is to develop a reduced risk imaging technique, which can be used to follow up patients after coronary intervention. After the intravenous injection of a contrast agent (iodine) two images are produced with monochromatic beams, bracketing the iodine K-edge.

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The purpose of this work was to demonstrate the feasibility of a new imaging technique called synchrotron radiation computed tomography (SRCT). This technique leads to a direct assessment of the in vivo concentration of an iodine- or gadolinium-labeled compound. Rats bearing C6 glioma were imaged by MRI prior to the SRCT experiment.

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NMR imaging allow specific study of contrast variations due to intravascular agents. It is possible to measure regional cerebral blood volume (rCBV). In brain tumor, this parameter allow to characterize tumoral vascularisation and blood brain barrier lesions.

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We present in this paper two imaging techniques using contrast agents assessed with in vivo experiments. Both methods are based on the same physical principle, and were implemented at the European Synchrotron Radiation Facility medical beamline. The first one is intravenous coronary angiography using synchrotron radiation X-rays.

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The application of synchrotron radiation in medical research has become a mature field of research at synchrotron facilities worldwide. In the relatively short time that synchrotrons have been available to the scientific community, their characteristic beams of UV and X-ray radiation have been applied to virtually all areas of medical science which use ionizing radiation. The ability to tune intense monochromatic beams over wide energy ranges differentiates these sources from standard clinical and research tools.

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Objective: The relationship between caseload size and self-perceived clinical effectiveness of mental health case managers was explored.

Methods: A 17-item instrument developed for the study, the Case Manager Personal Efficacy Scale (CMPES), was completed by 300 community mental health case managers in Australia. Efficacy scores were examined in relation to caseload size and to respondents' scores on the General Health Questionnaire.

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Background: It has been suggested that the switch to an angiogenic phenotype can separate the development of a tumor into two stages: the prevascular phase and the vascular phase. The purpose of the present work is to demonstrate the existence of an angiogenic switch in a longitudinal study of a brain tumor model during tumor growth by means of microvessel density measurements.

Materials And Methods: The study was performed on 32 rats bearing C6 glioma.

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Background And Purpose: Although the central processing of somatic pain has been dealt with in numerous brain imaging studies, the neural correlates of visceral pain have received much more limited attention. Our goal was to assess the feasibility of detecting brain activation patterns induced by rectal pain by means of functional MR imaging. We hypothesized that the cerebral processing of rectal pain would exhibit strong similarities with the central processing of somatic pain.

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Purpose: To assess the usefulness of the 0.9-ppm peak from amino acids (-CH3 moieties from valine, leucine, and isoleucine) for the differentiation of brain abscesses and tumors at in vivo hydrogen 1 magnetic resonance (MR) spectroscopy.

Materials And Methods: Amino acid concentrations were determined in vitro in 13 purulent samples from brain and nonbrain tissues and in nine aseptic fluids from necrotic brain tumors at two-dimensional (2D) 1H MR spectroscopy and liquid chromatography.

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The aim of this work was to evaluate the potential of T(2)-weighted, steady-state susceptibility-enhanced contrast magnetic resonance imaging (MRI), to characterize brain tumor heterogeneity and tumor vascularization. In vivo T(2)-weighted MRI experiments were carried out on normal rats (n = 11) and rats bearing C6 glioma (n = 17), before and after the injection of a remanent superparamagnetic contrast agent. The DeltaR(2) variations of the transverse relaxation rate due to the injection of the contrast agent were used to generate relative cerebral blood volume (CBV) maps.

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Purpose: To study the short term efficiency and safety of a new filtering procedure, the non-penetrating deep sclerectomy, in the treatment of open-angle glaucoma.

Methods: We conducted a retrospective study (January 1998-September 1998). Our material included a consecutive non-randomized series of 29 patients, 34 eyes in total.

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This study reports the MR spectroscopic patterns of two patients with bithalamic glioma. In one patient, phosphorus (31P) MR spectroscopy was performed. In both patients, the proton MR spectroscopic scans showed an increased creatine-phosphocreatine peak in the tumor.

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Objective: The purpose of this study was to investigate the perceptions of community staff regarding service process and quality, while a public mental health service integrated acute inpatient and continuing care components.

Methods: The study employed a naturalistic successive measures design in which community mental health staff completed a questionnaire on three occasions during the integration process.

Results: Staff perceived overall service quality to improve during the integration process with continuity of care being the area subject to greatest improvement.

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A 19-year-old woman reported difficulties in swallowing and breathing. A submucosal mass, shown by MR imaging in the retropharyngeal space, was the cause of her symptoms. Histologically, the mass proved to be a fibromyxoma.

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Neurosurgery is in essence a field of application development for robots, based on multimodal image guidance. Specific motorized tools have already been developed and routinely applied in stereotaxy to position a probe holder or in conventional neurosurgery to hold a microscope oriented towards a given target. The potentialities of these approaches have triggered industrial developments which are now commercially available.

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The low-affinity IgE receptor (FcepsilonRII/CD23) plays a role in IgE production. Cytokines participating in IgE synthesis also modulate CD23 expression on lymphocytes, but whether this modulation is different in atopic subjects remains unclear. We studied CD23 expression on B and T lymphocytes in 10 asthmatic patients with Dermatophagoides pteronyssinus hypersensitivity and 10 healthy non-atopic subjects.

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Magnetic resonance spectroscopy (MRS) is a noninvasive means of obtaining metabolic information complementary to magnetic resonance imaging. Its potential is particularly interesting in tissue characterization and follow-up of brain lesions. We present here a review of clinical applications together with a short development of the fundamental principles.

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A longitudinal study of peripheral blood lymphocyte subsets was performed in 23 renal allograft recipients treated with prophylactic antilymphocyte antibodies, CsA, and steroids. At day 0 samples were obtained before transplantation (Tx), and afterwards at months +1, +3, +6, +9, +12, +24, +36, and +48. In all patients, after the depletion of lymphoid subsets during antilymphocyte antibody treatment, CD8+ lymphocytes recovered and reached higher values than those observed prior to Tx.

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Neurosurgery is by excellence a field of application for robots, based on multimodal image guidance. Specific motorized tools have been already developed and routinely applied in stereotaxy to position a probe holder or in conventional neurosurgery to hold a microscope oriented towards a given target. The potentialities of these approaches have triggered industrial developments currently commercially available.

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