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R Voltz

Publications and source records attributed to R Voltz.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Bleeding atheroma. A nuclear magnetic resonance tomography differential diagnosis of dissection of the carotid artery].

Improved methods of imaging the cerebral vascular system have increased the detection of traumatic or spontaneous dissection of the vertebral and carotid arteries. Especially MRI allows direct demonstration of intramural hematomas that are a sign of dissection of the vessel wall. We report on a patient who had an acute onset of dysarthria and monocular blurred vision, which recurred several times. Doppler ultrasound showed stenosis in both internal carotid arteries with reduced velocity of the flow; angiography confirmed the stenosis, showing a long stretch of stenosis (70%) of the right and a short stretch of stenosis (60%) of the left internal carotid arteries. MRI demonstrated a narrowing of the lumen by an intramural mass, whose signal characteristics were typical for blood. The MRI findings were thus consistent with the diagnosis of a spontaneous dissection of the carotid arteries. Since the Doppler ultrasound follow-up showed no change during the following 3 days, we interpreted the MRI findings as an indication of bleeding in an atheroma. The carotid disobliteration, performed first on the left side and later on the right side, confirmed this interpretation. Since stenosis due to a fissuring atheroma or bleeding in an atheroma requires different therapy than a dissection, it is thus important to consider the possible differential diagnosis in interpreting the MRI.

Arteriosclerosis↗
PubMed1997

Highly purified oligo-His tagged human recombinant alpha(1)-AChR is immunogenic in vivo and suitable for T cell stimulation in vitro in experimental and human myasthenia gravis.

Using recombinantly expressed proteins for selection of antigen-specific T cell lines carries a high risk of selecting T cells specific for contaminating proteins. This risk is especially high for very hydrophobic proteins which are notoriously difficult to purify, such as the integral membrane protein acetylcholine receptor (AChR). We prepared a highly purified recombinant AChR by adding an oligo-histidine affinity-tag to the human alpha(1)-AChR and expressing it in E. coli. This allowed purification by Ni-NTA chromatography and subsequent electroelution from preparative SDS gel as purification steps, resulting in complete purity as assessed by silver stain on SDS-PAGE. This protein preparation induced fatal experimental allergic myasthenia gravis in Lewis rats. Furthermore, the protein could be used to select T cell lines from immunized Lewis rats and patients with myasthenia gravis. However, even with this highly purified protein, one of 8 Lewis rat T cell lines and 3 of 7 human T cell lines cross-reacted to E. coli control proteins. The results show that oligo-histidine tagged, highly purified human alpha(1)-AChR is highly immunogenic in vivo and in vitro.

Affinity Labels↗
PubMed1997

Sensitivity of delayed gadolinium-enhanced MRI in multiple sclerosis.

INTRODUCTION: We performed this study to define the sensitivity of delayed gadolinium-enhanced magnetic resonance imaging (MRI) in detecting active lesions in the brains of patients with multiple sclerosis (MS). MATERIAL AND METHODS: T1-weighted images were obtained in 27 patients with relapsing-remitting or secondary progressive MS before, 5-7 min and 20-30 min after the injection of 0.1 mmol/kg gadolinium-DTPA. RESULTS: One-hundred-and-three enhancing lesions were found on the early and 110 on the delayed scans (increase=6.4%). Six patients had 8 additional lesions in the delayed scans, while 1 patient had 1 more lesion on the early scan. Two of the 12 (17%) patients with no enhancing lesions on the early scans had 2 enhancing lesions on the delayed scans. The average increase of enhancing lesion detection with delayed scanning was 14.5% for those patients who already had enhancing lesions on the early post-contrast scans. A significant increase of the enhancing lesion volume was found with delayed scanning (P=0.004). CONCLUSION: These data indicate that it is possible to increase MRI sensitivity in detecting MS active lesions by delaying the scanning after gadolinium injection.

Adult↗
PubMed1997

Sensitivity and reproducibility of fast-FLAIR, FSE, and TGSE sequences for the MRI assessment of brain lesion load in multiple sclerosis: a preliminary study.

Fast fluid-attenuated inversion recovery (fast-FLAIR), fast spin echo (FSE), and turbo-gradient spin echo (TGSE), new pulse sequences for magnetic resonance imaging (MRI), are able to display multiple sclerosis (MS) lesions more conspicuously (fast-FLAIR) and with shorter imaging times (FSE, TGSE) than is conventional spin-echo MRI. In this study, we scanned 7 MS patients, using fast-FLAIR (18 axial brain slices), FSE (27 slices), and TGSE (9 slices) sequences in the same session, to compare the brain MRI lesion loads detected by these different sequences and the intraobserver reproducibility of these measurements. On the subset of slices (n = 9) covered by all three measurements, the mean lesion load was 7.577 mm3 on fast-FLAIR, 5.248 mm3 on FSE, and 3.080 mm3 on TGSE (p = 0.006) sequences. The mean intraobserver coefficients of variation were 2.92% for fast-FLAIR, 2.86% for FSE, and 4.31% for TGSE (not significant). These findings demonstrate that both fast-FLAIR and FSE sequences may be potentially useful for serial MRI studies for monitoring clinical trials, while TGSE might be useful for speeding diagnostic MRI in MS patients. Longitudinal, clinically correlated studies using these new MRI sequences are needed to confirm these preliminary data.

Brain↗
PubMed1997

Organization and patients' perception of palliative care: a crosscultural comparison.

The hospice model of care for patients with advanced diseases exists in almost all industrialized countries. To date, there have been no international or crosscultural comparisons of the organization and patient outcomes associated with hospice services in different parts of the world. This survey evaluated 159 patients in the USA, Germany and Japan. There were differences between countries in the time of first contact, who recommended palliative care first, the underlying diagnoses, the location of patients, and how consent for hospice care was obtained. Across all countries, there were similar levels of comfort and satisfaction with care. We conclude that the hospice philosophy addresses the basic needs of dying patients which are independent of cultural background, but may be adapted to very different cultures.

Aged↗
PubMed1997

Comparison of MR pulse sequences in the detection of multiple sclerosis lesions.

PURPOSE: To compare the sensitivity of conventional spin-echo, fast spin-echo, fast fluid-attenuated inversion recovery (FLAIR), and turbo gradient spin-echo MR sequences in the detection of multiple sclerosis lesions. METHODS: Conventional spin-echo, fast spin-echo, fast FLAIR, and turbo gradient spin-echo sequences were performed on a 1.0-T MR imager in seven patients with clinically definite multiple sclerosis. The images in each sequence were evaluated by two raters and consensus was reached by agreement. RESULTS: In comparing conventional spin-echo with fast spin-echo sequences, five lesions were seen only by conventional spin-echo and 63 were seen only by fast spin-echo; in comparing conventional spin-echo with fast FLAIR sequences, 18 lesions were seen only by conventional spin-echo and 109 only by fast FLAIR; in comparing conventional spin-echo with turbo gradient spin-echo sequences, 51 lesions were seen only by conventional spin-echo and seven only by turbo gradient spin-echo; in comparing fast spin-echo with fast FLAIR sequences, 45 lesions were seen only by fast spin-echo and 52 only by fast FLAIR. CONCLUSION: Fast spin-echo and fast FLAIR sequences improve the sensitivity of MR imaging in the detection of multiple sclerosis lesions with reduced acquisition time as compared with conventional spin-echo sequences. These sequences should therefore be considered for serial studies in patients with multiple sclerosis. The sensitivity of turbo gradient spin-echo was inferior to the other sequences, but its reduced acquisition time could make this technique the ideal choice for patients who cannot tolerate longer examination times.

Diagnosis, Differential↗
PubMed1996

BK virus encephalitis in an immunocompetent patient.

OBJECTIVES: To describe a previously healthy patient now suffering from monophasic encephalitis caused by a primary infection with BK virus and to discuss possible risk factors for developing BK virus encephalitis. DESIGN: Case report. SETTING: Referral hospital. PATIENT: The patient was examined on referral. MAIN OUTCOME MEASURES: The main diagnostic tests performed were serology, polymerase chain reaction on cerebrospinal fluid samples, and cranial magnetic resonance imaging. RESULTS: During the course of the patient's encephalitis, an IgM titer developed against polyomavirus, followed by anti-polyomavirus IgG. Wild-type BK virus was demonstrated in cerebrospinal fluid samples. Cranial magnetic resonance imaging showed diffuse reversible white matter changes most prominent on T2-weighted images. CONCLUSION: We conclude that diagnostic tests for BK, a human polyomavirus, should be included in the screening program for encephalitogenic pathogens.

Adult↗
PubMed1996

A high-resolution three-dimensional T1-weighted gradient echo sequence improves the detection of disease activity in multiple sclerosis.

In this study, we performed a post-contrast magnetization-prepared rapid acquisition gradient echo (MP RAGE) sequence with subsequent reconstruction of axial slices with 5-, 3-, and 1-mm thickness in 26 patients with multiple sclerosis (MS) to investigate the disease activity going on below the resolution of conventional scans. One hundred three enhancing lesions were detected using MP RAGE reconstructed with 1-mm-thick slices, 93 using MP RAGE reconstructed with 3-mm-thick slices and 82 using MP RAGE reconstructed with 5-mm-thick slices. The detection rate using 1-mm MP RAGE was 25.6% higher compared with 5-mm MP RAGE and 12% higher compared with 3-mm MP RAGE. Using 1-mm MP RAGE, we detected five enhancing lesions in 2 of the 12 patients (16.6%) who showed no enhancing lesions on the 5-mm MP RAGE and one enhancing lesion in 1 of the 10 patients (10%) who showed no enhancing lesions on the 3-mm MP RAGE. The increased sensitivity of 1-mm MP RAGE over the other two reconstruction slice thicknesses was due to improved detection of small lesions, located mainly in cortical/subcortical areas. These data indicate that the size of enhancing lesions in MS is highly variable, and that a significant proportion of disease activity goes undetected when performing conventional scans.

Adult↗
PubMed1996

Multiple sclerosis: prospective analysis of TNF-alpha and 55 kDa TNF receptor in CSF and serum in correlation with clinical and MRI activity.

The possibility of antagonizing tumor necrosis factor-alpha (TNF-alpha) in vivo with antibodies or soluble TNF receptor has focused much interest on the role of this cytokine in the natural course of MS. We studied nine patients prospectively and serially for one year (14 time points, 131 observations). TNF-alpha and the 55 kDa soluble TNF receptor were measured every 4 weeks in the serum and at defined time points in the CSF. Each value was correlated to clinical symptoms and to MRI measurements obtained on the same day. All patients with relapsing-remitting disease showed periodic increases of TNF concentrations. Overall, the association between serum TNF-alpha levels and bursts of Gd-DTPA enhancement on cranial MRI was not sufficiently tight to reach statistical significance. However, serum TNF levels > 50 pg/ml and measurable CSF levels were always associated with Gd-DTPA enhancing MRI lesions. Isolated high serum TNF peaks were noted during episodes of infection, hay fever or psychic stress. After treatment with glucocorticoids, TNF levels were suppressed for several months, whereas new Gd-DTPA enhancing lesions continued to appear. The concentrations of the soluble 55 kDa TNF receptor did not show marked fluctuations. These results are consistent with an active role of TNF-alpha in MS during periods of disease activity and provide further support for the clinical evaluation of anti-TNF therapies.

Adult↗
PubMed1996

Quantitative assessment of MRI lesion load in multiple sclerosis. A comparison of conventional spin-echo with fast fluid-attenuated inversion recovery.

In this study, we compared a fast fluid-attenuated inversion recovery (fast-FLAIR) sequence to conventional spin-echo (CSE) in the evaluation of brain MRI lesion loads of seven patients with clinically definite multiple sclerosis. Interleaved CSE (3000/20, 5 mm contiguous axial slices) and fast-FLAIR (9000/150/2200, 5 mm contiguous axial slices) sequences were performed on a 1.0 T machine. Lesions were counted consensually by two observers and then segmented independently by two other observers using a local thresholding technique, with subsequent manual editing in the case of poorly defined lesions. Four hundred and two lesions were detected in at least one of the two sequences: 128 were seen only on fast-FLAIR, 17 only on CSE. Forty-one lesions were larger on fast-FLAIR, while no lesion was considered larger on CSE. The numbers of periventricular (P = 0.05), cortical/subcortical (P = 0.02) and discrete (P = 0.05) lesions detected using fast-FLAIR were higher than those detected using CSE. The median lesion load was 7185 mm3 on CSE and 8418 mm3 on the fast-FLAIR, the average being 18% (range = 11.6-29%) higher on the fast-FLAIR images. Lesion contrast ratio was higher for lesions on the fast-FLAIR than on the CSE sequence (P < 0.0001). The percentages of poorly defined lesions which needed manual editing after the local thresholding technique was applied and the total time needed for the measurements were lower (P < 0.001) when fast-FLAIR images were used compared with CSE. This resulted in a reduced inter-rater coefficient of variation in measuring lesion volumes. Our data indicate that fast-FLAIR sequences are more sensitive than CSE in detecting multiple sclerosis lesion burden and that fast-FLAIR is a promising technique for natural history studies and clinical trials in multiple sclerosis.

Adult↗
PubMed1996

The use of intravenous immunoglobulins in the treatment of neuromuscular disorders.

Intravenous immunoglobulin is increasingly used in the treatment of neuromuscular disorders. Its efficacy has been proven in Guillain-Barré syndrome, chronic inflammatory demyelinating polyneuropathy, and Lambert-Eaton myasthenic syndrome. In addition, there is increasing evidence that it has beneficial effects in other neuromuscular disorders.

Drug Administration Schedule↗
PubMed1996

Spinal cord MRI in multiple sclerosis with multicoil arrays: a comparison between fast spin echo and fast FLAIR.

OBJECTIVES: To compare the sensitivity of fast spin echo (FSE) and of fast fluid attenuated inversion recovery (fast FLAIR) in detecting spinal cord lesions in multiple sclerosis. METHODS: With a 1.5 Tesla machine and a multicoil receiver array, FSE images (with two different pixel sizes) and fast FLAIR images of the spinal cord were obtained from 13 patients with multiple sclerosis. RESULTS: Twenty three lesions (10 cervical, 12 thoracic, and one lumbar) were found in seven patients (54%) using FSE with the larger pixel size. Seventeen lesions (seven cervical and 10 thoracic) were detected in the same seven patients using FSE with smaller pixel size. Nine lesions (five cervical and four thoracic) were found using fast FLAIR in six patients (46%). All the lesions found using fast FLAIR were detected using the other two techniques and all the lesions detected by FSE with smaller pixel size were detected using FSE and greater pixel size. CONCLUSION: Fast FLAIR sequences detect substantially fewer cord lesions in patients with multiple sclerosis.

Adult↗
PubMed1996

Reversible encephalopathy with cerebral vasospasm in a Guillain-Barré syndrome patient treated with intravenous immunoglobulin.

We report a patient with a reversible multifocal encephalopathy that developed 3 days after completion of treatment with intravenous immunoglobulin for Guillain-Barré syndrome. Magnetic resonance imaging showed reversible bioccipital white matter changes, and transcranial Doppler demonstrated transiently increased flow rates in all major cerebral arteries. We conclude that intravenous immunoglobulin therapy caused cerebral arterial vasospasm and a reversible encephalopathy.

Adult↗
PubMed1996

Comparison of triple dose versus standard dose gadolinium-DTPA for detection of MRI enhancing lesions in patients with MS.

We studied whether a triple dose of gadolinium-DTPA alone or in combination with delayed scanning increases the sensitivity of brain MRI for detecting enhancing lesions in patients with MS. We obtained T1-weighted brain MRI scans in two sessions for 22 patients with clinically definite MS. In the first session, we obtained one scan 5 to 7 minutes after the injection of 0.1 mmol/kg gadolinium-DTPA (standard dose). In the second session, 6 to 24 hours later, we obtained one scan before the two scans 5 to 7 minutes (for all patients) and one hour (for 11 patients) after the injection of 0.3 mmol/kg gadolinium-DTPA (triple dose). We detected 83 enhancing lesions in 14 patients when the standard dose of gadolinium-DTPA was used. The numbers of enhancing lesions increased to 138 (average increase 66%; p = 0.001) and the numbers of patients with such lesions to 18 (increase 28%) when we used the triple dose of gadolinium-DTPA. In addition, the total area per patient occupied by such lesions was greater (p < 0.0001) and lesion signal intensity higher (p = 0.0001) on the triple-dose scans than the standard-dose scans. There was an increase in the number of large enhancing lesions (p = 0.03) in the scans obtained 1 hour after the injection of the triple dose of gadolinium-DTPA. These data indicate that in patients with MS, a triple dose of gadolinium-DTPA can reveal many more enhancing lesions, which also appear larger. This suggests that the pathologic nature of "active" lesions in MS is heterogeneous, which might have impact on planning clinical trials.

Contrast Media↗
PubMed1995

The role of autoimmune T lymphocytes in the pathogenesis of multiple sclerosis.

Autoimmune T cells play a key role as regulators and effectors of autoimmune disease. In multiple sclerosis (MS), activated T cells specific for myelin components or other locally expressed autoantigens enter the CNS and recognize their antigen(s) on local antigen-presenting cells. After local stimulation, the T cells produce a plethora of cytokines and inflammatory mediators that have profound effects on the local cellular environment, induce and recruit additional inflammatory cells, and contribute to myelin damage. An increasingly detailed knowledge of these processes will greatly facilitate the development of new immunotherapies. This article focuses on the role of T cells in MS. We provide a brief overview of the principles of T-cell immunology, discuss the experimental techniques available for studying T cells, address the role of T cells in the pathogenesis of MS, and highlight modern concepts for immunotherapy.

Amino Acid Sequence↗
PubMed1994

[Palliative therapy in neurology].

Palliative therapy aims at increasing the quality of life in patients with a terminal illness. This article provides an overview of the available therapeutic options for the most important symptoms occurring in late-stage neurological disease, including restlessness, drowsiness, death-rattle, shortness of breath, pain, seizures, raised intracranial pressure, thirst and hunger.

Cause of Death↗