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Biomedical subjects

M Stehling

Publications and source records attributed to M Stehling.

12 recordsLinked to original sources
PubMed2000

Human monocytes express CD163, which is upregulated by IL-10 and identical to p155.

CD163 is a glucocorticoid-inducible member of the scavenger receptor cysteine-rich family of proteins. Previous reports have indicated that CD163 is highly expressed on human macrophages, but found on less than 50% of peripheral blood monocytes. We now show that >99% of all CD14 positive monocytes express CD163 and that monocyte derived dendritic cells express low levels of CD163. We also show that IL-10, like glucocorticoids, induces high CD163 expression on cultured human monocytes. Glucocorticoid induced CD163 expression was not inhibited by anti-IL-10 and was additive with IL-10 treatment, suggesting that glucocorticoids increase CD163 expression by an IL-10 independent mechanism. Other anti-inflammatory cytokines (IL-4 and IL-13) did not increase CD163 expression. In addition, we show that p155 (a previously identified monocyte/macrophage marker of unknown function) shares identity with CD163. Western blots and flow cytometric analysis of HEK 293 cells transfected with the cDNA for CD163 were positive when probed with either mAb RM3/1 (which recognizes CD163) or Mac 2-48 (which defines p155).

Animals↗
PubMed1999

Navigator echo-based respiratory gating for three-dimensional MR coronary angiography: results from healthy volunteers and patients with proximal coronary artery stenoses.

OBJECTIVE: The purpose of our study was to investigate the value of respiratory-gated three-dimensional (3D) MR angiography in identifying coronary arteries in healthy volunteers and in patients with proximal coronary artery stenosis and to compare the results with those of conventional coronary angiography. SUBJECTS AND METHODS: Twenty healthy volunteers and 20 patients with coronary artery stenosis were examined on a 1.5-T scanner with a retrospectively respiratory-gated 3D gradient-echo sequence. Visualization of the main coronary arteries was analyzed after curved multiplanar reconstructions. A six-point grading system was used to evaluate 400 vessel segments. The assessment of stenosis was performed by two observers who were unaware of the results of conventional coronary angiography. RESULTS: The proximal, middle, and distal segments of the coronary arteries were completely identified with or without luminal irregularities in 55%, 47%, and 20%, respectively, of the healthy volunteers. For the 20 patients, results were 69%, 44%, and 20%, respectively. For the assessment of coronary artery stenoses (n = 53), sensitivity was 73% and specificity was 50% after evaluation of the MR angiograms of all patients. A sensitivity of 79% and a specificity of 54% were found for evaluation of the MR coronary angiograms, with an image quality score of at least 3 (i.e., artery segments completely identified with major luminal irregularities). CONCLUSION: With the navigator echo MR imaging technique, a complete 3D visualization of the main coronary arteries was possible in cases with high image quality. However, further experience with and improvement of the navigator echo technique we used is necessary for reliable assessment of coronary artery stenosis.

Adult↗
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↗
PubMed1995

High-resolution activation mapping of basal ganglia with functional magnetic resonance imaging.

We investigated the activation of the putamen and the external and internal division of the globus pallidus in 12 normal volunteers during rapid supination and pronation of their right or left hand, using functional MRI (fMRI). We observed an increase in signal intensity varying from 3.1 +/- 1.2% to 23.4 +/- 2.3% during activation. Activated areas were predominantly contralateral to the moving hand and smaller than 5 mm2. These findings indicate that fMRI allows study of the normal function of basal ganglia and may be of value in the investigation of basal ganglia disorders.

Adult↗
PubMed1992

Dynamic studies of gadolinium uptake in brain tumors using inversion-recovery echo-planar imaging.

Echo-planar imaging has been used to observe the dynamics of Gd-DTPA uptake in brain tumors. It has been possible to examine both vascular uptake and diffusion across the blood-brain barrier in a single experiment, by using the IR-MBEST echo-planar sequence which combines a high temporal resolution (approximately 3 s) with strong T1 weighting. To model the uptake it is necessary to know the arterial concentration of Gd-DTPA; in this study the signal in the sagittal sinus was measured to avoid the need to take repeated blood samples. The time constant for transfer across the blood-brain barrier was measured to be between 20 and 1050 s for different tumors. The results of the modeling correlated with the results of other assessments of tumor vascularity.

Adult↗
PubMed1991

Clinical experience with contrast enhanced echo-planar imaging of the brain.

The overall effects of intravenous Gd-DTPA on tissue signal in intracranial tumors are complex depending on dose, time of administration, pulse sequence, and tissue structure. Ultrahigh speed EPI permits the kinetics of tissue enhancement in intracranial tumors to be studied during the "wash-in" equilibrium and "wash-out" phases. Ongoing studies employing dynamic scanning have shown it to be a valuable adjunct to a morphological study of tumors, providing an assessment of vascularity which is important in planning resection; and demonstrating areas with maximal breakdown of the blood-brain barrier which are most suitable for stereotactic biopsy. There are grounds for anticipating that the analysis of the temporal profile of enhancement may allow discrimination between different tumor types and provide information on factors which relate to the malignant potential of a single type.

Brain Neoplasms↗
PubMed1990

Echo planar imaging of an infant with pectus excavatum.

Echo planar imaging has enabled us to image safely and without sedation the thorax of an infant with pectus excavatum deformity. The heart was displaced into the left side of the thorax, and the right lung was calculated to be 1.6 times larger than the left lung.

Funnel Chest↗
PubMed1989

Snapshot imaging at 0.5 T using echo-planar techniques.

Echo-planar imaging using a magnetic field strength of 0.5 T has resulted in an improvement in image quality compared with recent images published at 0.1 T. The sensitivity of the technique to main magnetic field inhomogeneity and transient eddy currents has necessitated innovations in gradient and radiofrequency coil design. These improvements are described, and new variations in the echo-planar pulse sequence which provide better contrast and allow separate imaging of water and fat distributions are presented.

Abdomen↗
PubMed1988

Snapshot head imaging at 0.5 T using the echo planar technique.

The echo planar imaging (EPI) method and related variants of this technique can produce complete two-dimensional images from the data collected in a single experiment lasting a fraction of a second. EPI methods are used at 0.5 T to produce snapshot images of the human head with a spatial resolution of less than 2 mm.

Head↗
PubMed1988

Evaluation of infants by echo planar imaging after repair of diaphragmatic hernia.

Three infants were studied by echo planar imaging after repair of congenital diaphragmatic hernias. Total lung volume and individual lung volumes were estimated using echo planar imaging. In the two patients with left sided hernias, the right lung was more than twice as large as the left. The patient with a right sided hernia had developed emphysema on the right side, and the right lung was twice as large as the left when estimated by echo planar imaging. Echo planar imaging studies took less than five minutes to perform and no sedation was required.

Female↗
PubMedDate not supplied

Quantitative magnetic resonance imaging of vertebral bodies: a T1 and T2 study.

Multiple point T1 and T2 values of 424 vertebral bodies were measured and analysed. The influence of several factors including age, sex, location in the spine and status of neighbouring discs on the measured relaxation times were evaluated. The results indicate limitations in the region of interest approach. Vertebral bodies of different age, sex and location in the spine could not be distinguished. For heterogeneous tissues a more advanced form of image analysis appears to be essential. Diurnal factors resulting from the stress of normal ambulatory activity caused increased variation in vertebral body relaxation time values.

Adult↗