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T Nagel

Publications and source records attributed to T Nagel.

30 records · Page 2Linked to original sources
PubMed1994

Shear stress selectively upregulates intercellular adhesion molecule-1 expression in cultured human vascular endothelial cells.

Hemodynamic forces induce various functional changes in vascular endothelium, many of which reflect alterations in gene expression. We have recently identified a cis-acting transcriptional regulatory element, the shear stress response element (SSRE), present in the promoters of several genes, that may represent a common pathway by which biomechanical forces influence gene expression. In this study, we have examined the effect of shear stress on endothelial expression of three adhesion molecules: intercellular adhesion molecule-1 (ICAM-1), which contains the SSRE in its promoter, and E-selectin (ELAM-1) and vascular cell adhesion molecule-1 (VCAM-1), both of which lack the SSRE. Cultured human umbilical vein endothelial cells, subjected to a physiologically relevant range of laminar shear stresses (2.5-46 dyn/cm2) in a cone and plate apparatus for up to 48 h, showed time-dependent but force-independent increases in surface immunoreactive ICAM-1. Upregulated ICAM-1 expression was correlated with increased adhesion of the JY lymphocytic cell line. Northern blot analysis revealed increased ICAM-1 transcript as early as 2 h after the onset of shear stress. In contrast, E-selectin and vascular cell adhesion molecule-1 transcript and cell-surface protein were not upregulated at any time point examined. This selective regulation of adhesion molecule expression in vascular endothelium suggests that biomechanical forces, in addition to humoral stimuli, may contribute to differential endothelial gene expression and thus represent pathophysiologically relevant stimuli in inflammation and atherosclerosis.

Cell Adhesion↗
PubMed1994

[Volume determination with 3D ultrasound exemplified by aneurysms of the abdominal aorta].

Ultrasound is the first diagnostic method concerning initial and follow-up investigations of patients with abdominal aortic aneurysms. The indication is given by threatening rupture when disease is progressing. The aim of the presented study was to find out the applicability of 3D ultrasound and volumetry and to elaborate possible advantages of the new method in comparison with 2D sonography concerning the estimation of volumes. Preliminary investigations of defined volumes of waterfilled balloons confirmed the accuracy of +/- 4% (4 investigators) and the reliability of +/- 2% (10 investigations). With well-defined rating categories 3D scans were found to be quite good as well as excellent in 55% of the processed 3D data. Estimation of volume using 2D linked ellipsoid formula showed higher results in 92% of the cases than performing 3D volumetry. For a high accuracy of 3D volume estimation, contouring of 5 representative slices was quite sufficient. The presented results suggest a high accuracy and reliability of the new method. Further clinical investigations are necessary to find out the clinical relevance concerning the follow-up of patients with abdominal aortic aneurysms.

Aged↗
PubMed1993

What is the mind-body problem?

The mind-body problem exists because we naturally want to include the mental life of conscious organisms in a comprehensive scientific understanding of the world. On the one hand it seems obvious that everything that happens in the mind depends on, or is, something that happens in the brain. On the other hand the defining features of mental states and events, features like their intentionality, their subjectivity and their conscious experiential quality, seem not to be comprehensible simply in terms of the physical operation of the organism. This is not just because we have not yet accumulated enough empirical information: the problem is theoretical. We cannot at present imagine an explanation of colour perception, for example, which would do for that phenomenon what chemistry has done for combustion--an explanation which would tell us in physical terms, and without residue, what the experience of colour perception is. Philosophical analyses of the distinguishing features of the mental that are designed to get us over this hurdle generally involve implausible forms of reductionism, behaviouristic in inspiration. The question is whether there is another way of bringing mental phenomena into a unified conception of objective reality, without relying on a narrow standard of objectivity which excludes everything that makes them interesting.

Animals↗
PubMed1984

Gonadal tumors in patients with gonadal dysgenesis and sex chromosomal rings and fragments.

Patients with female phenotypes and dysgenetic gonads harboring testicular tissue have a markedly increased risk of developing gonadal tumors. Cytogenetic demonstration of Y chromatin is the currently accepted criterion for performing prophylactic gonadectomies in these women. We studied four patients with dysgenetic gonads containing either testicular tissue or germ cell tumors. All had small sex chromosomal fragments which could not be characterized by conventional cytogenetic studies. Clinical features, DNA replication studies, and immunologic assays of Xga and H-Y antigens failed to correlate consistently with the gonadal histology. We recommend prophylactic gonadectomies and subsequent hormone replacement in all patients with female phenotypes, gonadal dysgenesis, and cytogenetically indeterminate sex chromosomal fragments.

Adolescent↗
PubMed1981

Histiocytosis X and pregnancy.

Histiocytosis X is associated with a pathologic proliferation of mononuclear histiocytes in the reticular endothelial system. Different clinical manifestations of this group of disorders may occur. Pregnancy and histiocytosis X infrequently occur simultaneously. Four cases previously reported along with 1 new case of histiocytosis X and pregnancy are reviewed in this report. Only chronic histiocytosis X, Hand-Schüller-Christian disease (HSCD), has been reported to occur during pregnancy. The most frequent complication during pregnancy was the onset or exacerbation of diabetes insipidus, as frequently seen with this disorder. The possibility that HSCD may alter pituitary function may contribute to the infrequent occurrence of pregnancy in patients with this disorder.

Adult↗
PubMedDate not supplied

[Arthroosteitis pustulosa, spondarthritis hyperostotica pustulo-psoriatica, SAPHO syndrome: clinical experiences and review of the literature].

Pustulotic arthroosteitis is characterized by the association of inflammatory and hyperostotic skeletal changes, primarily of the anterior chest wall, and chronic recurrent skin lesions of the palms and soles known as pustulosis palmaris et plantaris. Since its first description by Sonozaki in 1981 in Japan, it has also been reported by several European authors and become widely accepted as a separate entity within the spectrum of the seronegative spondylarthropathies. In this report, we describe 11 cases seen in our clinic in the years 1985 to 1992. Course and severity of the disease varied greatly among individual patients. In four of them a difference of up to 6 years between the onset of skin and skeletal symptoms were noted. Besides chronic recurrent nonspecific osteomyelitis in two cases, neither an association to other rheumatic or dermatologic diseases nor to HLA-B27 could be found. Corticosteroids, non-steroidal anti-inflammatory drugs, immunosuppressive agents, and antibiotics were all used with uncertain therapeutic success. Based on these data, we suppose that pustulotic arthroosteitis is more common in Germany than previously thought, and has to be considered as an important differential diagnosis of sternoclavicular arthritis. In a review of the available literature, the current opinions on nomenclature, etiology, pathogenesis, and treatment are discussed.

Adult↗