Search PubMed⌕ Search

Biomedical subjects

J Braun

Publications and source records attributed to J Braun.

At least 127 records · Page 7Linked to original sources
PubMed2002

Imaging and scoring in ankylosing spondylitis.

Ankylosing spondylitis (AS) is the prototype of the spondyloarthritides (SpA). AS is a disease subset but also a possible outcome of SpA. Early diagnosis of sacroiliitis, the most frequent clinical symptom frequently accompanied by inflammatory back pain and other inflammatory lesions of the spine such as spondylitis and spondylodiscitis, can be visualized early by magnetic resonance imaging (MRI). Spinal inflammation can be demonstrated by MRI using either the fat-saturating short tau inversion recovery (STIR) technique or by application of the contrast agent gadolinium-diethylenetriamine pentaacetic acid (DTPA). This is especially useful in early and active disease, in young women and in children, and for the differential diagnosis of septic sacroiliitis. Because of the efficacy of the novel biological agents directed against tumour necrosis factor-alpha (TNF-alpha) - such as infliximab and etanercept - in SpA there is a need for spinal imaging techniques more sensitive than conventional X-rays. The available scoring tools are reviewed and novel approaches using MRI are presented.

Adult↗
PubMed2002

Ankylosing spondylitis and current disease-controlling agents: do they work?

In contrast to rheumatoid arthritis (RA), the concept of disease modification in ankylosing spondylitis (AS) remains to be clarified. Endpoint measures employed in AS trials primarily assess features related to symptomatology while endpoints considered more relevant to the concept of disease modification, such as spinal mobility, acute-phase reactants and radiological progression, either lack sensitivity to change or have not been comprehensively validated. NSAIDs alleviate symptoms of AS but most trials have been short term, precluding meaningful conclusions regarding disease modification. Among disease-modifying therapies used in RA, sulfasalazine has been studied in several controlled trials mostly in patients with longstanding disease, effect sizes being small and limited to those with peripheral synovitis. No conclusions can be drawn from the limited studies evaluating methotrexate.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed2002

Therapy for ankylosing spondylitis: new treatment modalities.

The therapeutic options for patients suffering from the more severe forms of spondyloarthritis (SpA) have been rather limited in recent decades. There is now accumulating evidence that anti-tumour necrosis factor (anti-TNF) therapy is highly effective in SpA, especially in ankylosing spondylitis (AS) and psoriatic arthritis (PsA). Based on the data recently published on more than 200 AS patients, and more than 100 PsA patients, this treatment seems to be even more effective than it is in rheumatoid arthritis (RA). The two major anti-TNF-alpha agents currently available, infliximab (Remicade) and etanercept (Enbrel), are approved for the treatment of RA in Europe and in the USA. The situation in SpA is different from RA because there is an unmet medical need, especially in AS, because disease-modifying anti-rheumatic therapy is not available for severely affected patients. Thus, TNF blockers might even be considered first-line immunosuppressive treatment in patients with active AS who are not sufficiently treated with non-steroidal anti-inflammatory drugs (NSAIDs). For infliximab, a dose of 5mg/kg was required, and intervals between 6 and 12 weeks were necessary for constant suppression of disease activity - a major aim also for long-term treatment. However, it remains to be shown whether patients benefit from long-term therapy and whether radiological progression and ankylosis can be stopped. The optimal doses of infliximab might well be determined individually. Allergic reactions and increased susceptibility to tuberculosis are rare side-effects which need to be recognized early. As it stands now, the benefits of anti-TNF therapy in AS seem to outweigh these shortcomings. The efficacy of etanercept was first demonstrated in PsA. A double-blind study has now been performed in AS - with similar results. There is preliminary evidence that both agents also work in other SpA such as undifferentiated SpA. Hopefully, both agents will be approved soon for the short-term treatment of severe SpA. In parallel, studies should be performed to document the long-term efficacy and safety of this treatment.

Antirheumatic Agents↗
PubMed2001

Brain areas specific for attentional load in a motion-tracking task.

Although visual attention is known to modulate brain activity in the posterior parietal, prefrontal, and visual sensory areas, the unique roles of these areas in the control of attentional resources have remained unclear. Here, we report a dissociation in the response profiles of these areas. In a parametric functional magnetic resonance imaging (fMRI) study, subjects performed a covert motion-tracking task, in which we manipulated "attentional load" by varying the number of tracked balls. While strong effects of attention--independent of attentional load--were widespread, robust linear increases of brain activity with number of balls tracked were seen primarily in the posterior parietal areas, including the intraparietal sulcus (IPS) and superior parietal lobule (SPL). Thus, variations in attentional load revealed different response profiles in sensory areas as compared to control areas. Our results suggest a general role for posterior parietal areas in the deployment of visual of attentional resources.

Adult↗
PubMed2001

Neural correlates of attention and working memory deficits in HIV patients.

OBJECTIVES: To evaluate the neural correlates of attention and working memory deficits in patients with HIV-1. METHOD: fMRI was used to evaluate brain activity in 11 patients with HIV and 11 age-, sex-, education-, and handedness-matched seronegative subjects, while performing a battery of tasks that required different levels of attention for working memory. RESULTS: Patients with HIV showed greater brain activation (blood oxygenation level dependent signal changes) in some regions compared with control subjects while performing the same tasks. For the simpler tasks, patients with HIV showed greater activation in the parietal regions. However, with more difficult tasks, patients with HIV showed greater activation additionally in the frontal lobes. Reaction times during these tasks were slower but accuracy was similar in the patients with HIV compared with control subjects. CONCLUSION: Injury to the neural substrate caused by HIV infection may necessitate greater attentional modulation of the neural circuits, hence a greater use of the brain reserve; additional activation of the frontal lobes is required to perform the more complex tasks. The task-dependent increased frontal activation in patients with HIV suggests that the neural correlate of attentional deficits may be excessive attentional modulation as a result of frontostriatal brain injury.

AIDS Dementia Complex↗
PubMed2001

Segregation of granular media by diffusion and convection.

A diffusion-convection equation is used to model granular segregation within a mixture of particles of different size, shape, or surface structure in a vertical vessel. Convection describes competition between species in vertical direction whereas random noise (shaking) allows particles to exchange positions. For two species it is shown that the moving grains converge to a unique distribution along the vertical scale. For more than two species it is shown that at least one equilibrium distribution exists (there are examples with multiple equilibria). For a class of models with simple competition laws, uniqueness of the equilibrium in all dimensions is shown.

Journal Article↗
PubMed2001

Epithelial membrane protein 2, a 4-transmembrane protein that suppresses B-cell lymphoma tumorigenicity.

A murine homologue of the epithelial membrane protein 2 (EMP2) gene was identified in a search for genes associated with B-cell lymphoma tumorigenicity by using suppression subtractive hybridization. Expression of EMP2 messenger RNA in primary mouse tissues was limited to certain epithelial cell types and the peritoneal lymphoid compartment. EMP2 was expressed in the poorly tumorigenic DAC B-lymphoma cell line but was significantly down-regulated in a subline selected for in vivo tumor formation in Balb/c mice. Recombinant restoration of EMP2 expression in the subline suppressed its tumorigenicity, suggesting that loss of EMP2 was a causal factor in the malignant phenotype. Recombinant overexpression of EMP2 was studied in B lymphoma and NIH3T3 cells. EMP2 in both cell types induced cell death on serum deprivation. EMP2-induced cell death correlated with the expression level of EMP2 protein and was prevented by caspase inhibitors Z-VAD and Z-DEVD. These findings for the first time describe an apoptotic effect of a GAS3 family gene in lymphocytes. They also suggest that EMP2 may influence B-lymphoma tumorigenicity through a functional tumor suppressor phenotype. (Blood. 2001;97:3890-3895)

3T3 Cells↗
PubMed2001

Atovaquone suspension for treatment of Pneumocystis carinii pneumonia in HIV-infected patients.

OBJECTIVE: To describe clinical experience with atovaquone suspension for the treatment of Pneumocystis carinii pneumonia (PCP) in HIV-infected patients. DESIGN: A retrospective chart review. METHODS: The medical records of 54 HIV-infected patients with PCP treated with atovaquone were examined. The outcomes of 34 patients treated with atovaquone suspension (750 mg twice a day) were compared with those of 20 patients treated with atovaquone tablets (750 mg three times a day). RESULTS: The proportion of patients successfully treated was similar with the suspension (74%) and tablet (70%) formulations of atovaquone. The proportion of patients with an inadequate response to therapy was lower for patients treated with atovaquone suspension (15%) than tablets (30%). Both formulations were well tolerated. CONCLUSION: Atovaquone suspension is effective and well tolerated for the treatment of PCP.

AIDS-Related Opportunistic Infections↗
PubMed2001

[Non-neoplastic hypertrophic osteoarthropathy due to infected aortic prosthesis. Diagnostic imaging aspects].

Secondary hypertrophic osteoarthropathy of the legs is a rare complication of arterial graft surgery. The syndrome is composed of arthralgias, clubbing of the toes and periostosis of the long bones and is usually associated with an infected aortic prosthesis. Often a CT-guided biopsy is performed in order to identify the graft as the primary focus. In addition to the lamellar periostosis demonstrable by conventional radiographs, a vast edema of the bone marrow and surrounding soft tissue is disclosed by MRI. Imaging promotes the early surgical reintervention.

Aorta, Abdominal↗
PubMed2001

[Glucocorticoid-induced osteoporosis].

Osteoporosis due to steroid therapy is one of the most frequent and serious adverse events of antirheumatic therapy. The greatest loss of bone occurs during the 1st year of steroid intake, with the largest loss in the spine. Up to 50% of the patients, mostly postmenopausal women, suffer vertebral fractures. The prevalence of osteoporosis in 60-year-old patients with rheumatoid arthritis (RA) is more than double compared to the normal population. There are more risk factors other than age, gender, and menopause. Independent from the underlying disease, glucocorticoid therapy is associated with a high risk of osteoporosis development. Among the clinical manifestations of osteoporosis, fractures of the vertebrae, hips, and ribs are the most common. In clinical practice, bone density measurements are mostly performed with the dual-energy X-ray absorptiometry (DXA) technique. Since prevalent vertebral fractures are strongly predictive of new fractures, X-rays of the lumbar and thoracic spine are indicated in patients who are scheduled to receive steroid therapy for > 3 months. The value of serologic bone markers has not yet been clearly established. On the basis of these risks and the high prevalence of already manifest osteoporosis, there is a clear indication for osteoprotective therapy in RA. Bisphosphonates and active vitamin D metabolites play an important role for therapy and prophylaxis of steroid-induced osteoporosis. In rheumatology it is often necessary to administer bisphosphonates intravenously due to the disability of the patients. The clear necessity for prophylaxis and therapy of steroid-induced osteoporosis must be stressed. Efforts should be intensified to ensure even more consistent application in daily practice. Doctors should treat their steroid patients on the basis of the clear-cut indications for intervention despite budget problems.

Absorptiometry, Photon↗
PubMed2001

Volume-selective proton MR spectroscopy for in-vitro quantification of anticonvulsants.

Administration of anticonvulsant drugs is clinically monitored by checking seizure frequency and by determining the serum concentration of the drug. In a few reports, drug concentrations in brain parenchyma have been determined using ex vivo techniques. Little is known about the in vivo concentration in the brain parenchyma. Our goals were to characterise the NMR spectra of the anticonvulsants at therapeutic concentrations, to determine the minimum detectable concentrations, and to quantify the drugs noninvasively. Volume-selective 1H-MR spectroscopy (MRS) was performed under standard clinical conditions using a single-voxel STEAM (stimulated-echo acquisition mode) sequence at 1.5 T. Spectra of the anticonvulsants carbamazepine, phenobarbital, phenytoin and valproate were acquired in vitro in hydrous solutions at increasing dilution. Phenytoin, phenobarbital and valproate were detectable below maximum therapeutic serum concentrations. Within therapeutic ranges, there was good agreement between concentrations determined by 1H-MRS and those by standard fluorescence polarisation immunoassay. Due to the absence of signals of brain metabolites, the aromatic protons of phenobarbital, phenytoin and carbamazepine, with resonance lines around 7.4 ppm, allow the drugs to be detected. Valproate, with two resonances around 1.2 ppm, should be differentiable from potential brain metabolites using nonlinear analysis of the brain spectrum. Volume-selective 1H-MRS is therefore expected to be able to monitor anticonvulsant therapy in vivo.

Anticonvulsants↗
PubMed2001

[Current status of therapeutic approaches in spondyloarthropathies].

Anti-TNF therapy seems to be highly effective in AS. Based on the available results, this treatment seems to be at least as effective as in RA. Furthermore, because no other treatments are available for AS--in contrast to RA or psoriatic arthritis--infliximab might even become a first-line immuno-suppressive treatment in patients with severe, active AS. A dosage of 5 mg/kg seems to be required and intervals between 6-12 weeks seem to be necessary depending on the disease activity. It remains to be shown what the long-term effects are, whether the patients benefit from long-term therapy and whether radiological progression and ankylosis can be stopped. Allergy, lupus-like diseases and tuberculosis are rare side effects which need to be addressed. At first glance, the possible benefits of anti-TNF therapy seem to outweigh these shortcomings.

Antibodies, Monoclonal↗
PubMed2001

[Technique and value of arthrosonography in rheumatologic diagnosis. 1: Ultrasound diagnosis of the knee joint].

Within the last few years, ultrasonography (US) of joints has attained a firm position for the diagnosis of joint diseases. Degenerative as well as inflammatory changes can be recognized using this method. With new, higher resolution techniques even bone surfaces and tendon textures can be visualized in greater detail. The advantages of sonography are general availability and low costs. When used properly, as a non-invasive procedure US has no detrimental effects on patients. The disadvantages of this technique result from its physical limitations, such as high reflection of US on bone and the negative correlation between resolution and penetration which makes US imaging difficult in deeper regions. The current technical development of probes and imaging processing, however, promises better deep structure imaging in the future. The quality of ultrasound examination always depends on the technical equipment, as well as on the patients' individual tissue constitution and the experience of the physician. It is possible to avoid misinterpretation and to increase the diagnostic value of US by using a standardized technique and professional knowledge of the specific aspects of the method. The significance of qualified education and sufficient training of sonographers is to be stressed. The aim of this article is to deliver a basic contribution to the standardization and quality assurance of joint US and to indicate the value of this method. In addition to the overview the authors propose guidelines for performance and interpretation of joint US. Due to the major significance of the knee joint in rheumatology it was decided to begin the work in this area.

Arthritis, Rheumatoid↗