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71.
The Topography of Non-Linear Cortical Dynamics at Rest, in Mental Calculation and Moving Shape Perception 总被引:3,自引:0,他引:3
Andreas Meyer-Lindenberg Ulrike Bauer Stefan Krieger Stefanie Lis Kinga Vehmeyer Georg Schüler Bernd Gallhofer 《Brain topography》1998,10(4):291-299
Differential cortical activation by cognitive processing was studied using dimensional complexity, a measure derived from nonlinear dynamics that indicates the degrees of freedom (complexity) of a dynamic system. We examined the EEG of 32 healthy subjects at rest, during a visually presented calculation task, and during a moving shape perception task. As a nonlinear measure of connectivity, the mutual dimension of selected electrode pairs was used. The first Lyapunov coefficient was also calculated. Data were tested for non-linearity using a surrogate data method and compared to spectral EEG measures (power, coherence). Surrogate data testing confirmed the presence of nonlinear structure in the data. Cognitive activation led to a highly significant rise in dimensional complexity. While both tasks activated central, parietal and temporal areas, mental arithmetic showed frontal activation and an activity maximum at T3, while the moving shape task led to occipital activation and a right parietal activity maximum. Analysis of mutual dimension showed activation of a bilateral temporal-right frontal network in calculation. The Lyapunov coefficent showed clear topographic variation, but was not significantly changed by mental tasks (p<.09). While dimensional complexity was almost unrelated to power values, nonlinear (mutual dimension) and linear (coherence) measures of connectivity shared up to 37% of variance. Data are interpreted in terms of increased cortical complexity as a result of recruitment of asynchronously active, distributed neuronal assemblies in cognition. The topography of nonlinear dynamics are related to neuropsychological and neuroimaging findings on mental calculation and moving shape perception. 相似文献
72.
Martin Juenemann Holger Nef Helge Möllmann Pratibha Singh Christian Troidl Patrick Schramm Manfred Kaps Tibo Gerriets Franz Blaes Marlene Tschernatsch 《Immunobiology》2019,224(2):220-222
Background
An association between Tako-Tsubo cardiomyopathy (TTC) and underlying malignancies has been observed, suggesting that TTC might be the consequence of paraneoplastic phenomena. This study investigates the presence of autoantibodies against cardiomyocytes as well as adrenergic (β1, β2) and muscarinic (M2) receptors in patients with TTC.Methods and results
Serum from 20 TTC patients and 20 controls with ischemic heart disease was obtained. Indirect immunofluorescence testing for intracellular autoantibodies against cardiomyocytes showed a homogenous distribution, as in both groups 9 of 20 sera displayed a characteristic binding pattern of antibodies including vascular walls and intracellular structures. Flow cytometry analysis revealed no difference between TTC and controls in the binding of autoantibodies to the surface antigens of cardiomyocyte HL-1 cells (p?=?0.569, t-test). Flow cytometry analysis of nontransfected wild type cells (p?=?0.633, t-test), M2 receptor-transfected cells (p?=?0.687, t-test), β1 receptor-transfected cells (p?=?0.444, t-test) and β2 receptor-transfected cells (p?=?0.632, t-test) showed similar results for control and TTC sera. Likewise, the binding pattern of TTC patients with a history of neoplasia compared to those without or to controls did not differ significantly (p?>?0.05, u-test).Conclusion
Findings suggest that the presumed paraneoplastic etiology of TTC cannot be attributed to the formation of these antibodies. 相似文献73.
Georg W. Oertel 《Journal of molecular medicine (Berlin, Germany)》1961,39(9):492-493
Ohne Zusammenfassung 相似文献
74.
Ohne Zusammenfassung 相似文献
75.
Gambichler T Moussa G Sand M Sand D Orlikov A Altmeyer P Hoffmann K 《Journal of biomedical optics》2005,10(6):064030
Noninvasive imaging techniques might be of particular diagnostic value for studying and monitoring cutaneous inflammatory conditions such as contact dermatitis. We evaluate acute allergic contact dermatitis (AACD) by means of optical coherence tomography (OCT) and correlate the clinical grading of patch test reactions with the findings obtained from OCT. Twenty positive patch test reactions (+, n = 6; ++, n = 7; +++, n = 7) are investigated using a conventional OCT scanner. In comparison to the control sites, OCT of AACD showed pronounced skin folds, thickened and/or disrupted entrance signals, and a significant increase in epidermal thickness. Moreover, clearly demarcated signal-free cavities within the epidermis and considerable reduction of dermal reflectivity are demonstrated by OCT. Notably, the latter findings strongly correlate with the clinical patch test grading. OCT may be a useful tool for visualization of micromorphological features of AACD. However, before OCT can be employed as an objective parameter in grading severity of patch test reactions, larger studies are required that correlate clinical patch test readings and OCT findings with histopathology. 相似文献
76.
The mechanisms of cell adhesion to the extracellular matrix (ECM) which are of fundamental importance for function, survival, and growth of cells involve the formation of focal adhesions to facilitate integrin signaling. Recently, it became evident that focal adhesions are not stable but move to enable cell migration and ECM formation. We examined the number, size, and dynamic behavior of focal adhesions in living MG-63 osteoblastic cells, which were cultured on titanium surfaces with different roughnesses and on stainless steel (SS). As a marker for focal adhesions we used GFP-tagged vinculin, a cytoskeletal protein. Focal adhesions were smaller on titanium and on SS than on collagen-coated glass coverslips. The corundum-blasted rough surface of titanium induced the smallest adhesions. On all the surfaces that we have tested, we observed a mobility of focal adhesions. On collagen-coated coverslips focal adhesions moved with a speed of 60 nm/min. The speed was reduced on titanium and still more restricted on SS. The topography did not affect the mobility of focal adhesions. We conclude that on the material surfaces that we have studied a reduced mobility of focal adhesions may strengthen the linkages between cell and ECM but impair the ability to dynamically organize and remodel the ECM. The results may have a great impact in the functional evaluation of tailored biomaterial surfaces for the application in tissue engineering. 相似文献
77.
Georg Brehmer Karl Heinz Hölzer Gerhard Binzus 《Journal of molecular medicine (Berlin, Germany)》1963,41(12):577-580
Zusammenfassung Es wird ein neues Verfahren zur automatischen Untersuchung von Enzymkinetiken angegeben. Die Umsatzgeschwindigkeit einer Enzymreaktion in Abhängigkeit von jeweils einer veränderlichen Größe wird hierbei am durchlaufenden Reaktionsgemisch kontinuierlich gemessen und registriert. Unabhängige Veränderliche kann eine Konzentration (z. B. Substrat-, Coenzym-, Wasserstoffionenkonzentration) oder die Temperatur sein. Am Beispiel der Ermittlung einer Aktivitäts-pS-Kurve (Koordinaten:v=Umsatzgeschwindigkeit;pS=negativer Logarithmus der Substratkonzentration) wird das Verfahren im Einzelnen beschrieben. Unsere Methode eignet sich bisher zur Untersuchung von Enzymen, deren Umsatz durch Messung der Lichtabsorption erfaßbar ist. Als Beispiel werden Aktivitäts-pS-Kurven von Lactatdehydrogenase aus menschlichem Herzmuskel- und Leberhomogenisat sowie von Kaninchenmuskel-LDH gezeigt und die ermittelten Michaeliskonstanten angegeben. 相似文献
78.
Heike Nave Susanne Kuhlmann Georg Brabant Reinhard Pabst 《Experimental and toxicologic pathology》2003,55(1):45-49
Leptin, a potent anorectic, 16-kDa, adipose tissue-derived protein, predominantly acts in hypothalamic nuclei, signaling obesity and modulating ingestive behavior. To reach this brain area, leptin, probably has to cross the blood-brain barrier (BBB). In some cases of obesity, enhanced leptin levels in the blood do not result in anorectic effects, probably due to an altered leptin transport across the BBB. Therefore, we investigated the BBB in lean and diet-induced obese Lewis rats. To obtain information about the presence of microvessels with barrier dysfunction we examined three brain areas (hypothalamus, cortex, hippocampus) using a monoclonal antibody which detects intact microvessels of the BBB (anti-endothelial barrier antigen, anti-EBA). The results showed a significantly reduced EBA staining in the brain sections of the obese animals, except the hippocampus, compared to the control group. In a second step we injected I125-labeled leptin intravenously (i.v.) in permanent i.v.-cannulated, unrestrained Lewis rats (lean and obese). We measured the radioactivity in the cerebrospinal fluid after puncture of the cisterna magna, in the blood and brain tissue 90 min after injection. The leptin content in the cerebrospinal fluid and brain was not reduced in obese compared to lean rats, thus showing a similar transport capacity of the BBB in both experimental groups. Therefore, the results of the in vivo investigations do not indicate an impairment of the BBB in diet-induced obesity, despite the immunohistological findings. Further functional and morphological studies are necessary to evaluate the specific role of other organs and distinct forms of leptin (free and protein-bound) in the pathogenesis of diet-induced obesity. 相似文献
79.
Schwarz C Hauser P Steininger R Regele H Heinze G Mayer G Oberbauer R 《Laboratory investigation; a journal of technical methods and pathology》2002,82(7):941-948
SUMMARY: In renal transplantation, postischemic acute renal failure (ARF) develops in more than 20% of patients. We investigated whether tubular epithelial cells obtained from donor kidneys without subsequent ARF express a different pattern of survival genes, compared with cells from kidneys exhibiting ARF. Donor kidney biopsy specimens were obtained before transplantation from eight recipients of cadaveric kidneys with primary graft function (CAD-PF), eight patients with biopsy-proven ARF without rejection (CAD-ARF), and eight recipients of living donor kidneys with primary graft function (LIV). One thousand proximal tubular epithelial cells per biopsy specimen were isolated by laser capture microdissection. Quantitative analysis of apoptosis and the apoptosis regulatory genes Bcl-2, Bcl-xL, and Bax were performed by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling staining and real-time PCR, respectively. Primary cultures of human proximal tubular epithelial cells served as calibrator. The number of apoptotic cells was significantly higher in CAD-ARF compared with LIV and CAD-PF (1.5 +/- 1.1% [p < 0.05] vs. 0.3 +/- 0.2% vs. 0.4 +/- 0.2%; mean +/- SD). The apoptosis inhibitors Bcl-2 and Bcl-xL were significantly up-regulated in renal tubular cells of recipients without ARF compared with CAD-ARF. The ratios of Bcl-2/GAPDH normalized to calibrator were as follows: LIV 48 +/- 30, CAD-PF 38 +/- 55, and CAD-ARF 5 +/- 7 (p < 0.05). The corresponding ratios for Bcl-xL were as follows: LIV 6 +/- 6, CAD-PF 5 +/- 3, and CAD-ARF 1 +/- 1 (p < 0.05). No difference in the expression of the proapoptotic Bax could be observed. These data suggest that failure of proximal tubular cells to respond to injury by up-regulation of survival factors from the Bcl-2 family contributes to postischemic ARF in patients after cadaveric renal transplantation. 相似文献
80.
Walter Schuler Georg Lehle Eberhardt Weiler Eckehart Klsch 《European journal of immunology》1982,12(2):120-125
The primary antibody response in BALB/c mice to the T-independent bacterial antigen dextran B1355S [alpha(1 leads to 3)dextran] (Dex) was studied by means of isoelectric focusing, hemagglutination and immunodiffusion techniques. In response to a single immunization with 10 micrograms Dex all mice produce specific IgM antibodies. In addition, about 30% of conventionally raised BALB/c and BALB/c nu/ + mice, but 95% of germ-free (GF)-raised normal BALB/c and 100% of athymic BALB/c nu/nu mice produce specific IgG class anti-Dex antibodies. These antibodies include all IgG subclasses, carry predominantly the lambda light chain and the cross-reactive J558 idiotype and are specific for the alpha(1 leads to 3)glucosidic linkage. As compared to athymic and GF-raised mice, conventionally raised mice exhibit only a weak IgG response. The pronounced IgG production of GF-raised mice was not altered when adult mice were removed from their GF environment and housed under conventional conditions for several weeks prior to immunization with Dex. Reconstitution with isolated splenic T cells from conventionally raised, unprimed BALB/c mice reduces the remarkable capacity of BALB/c nu/nu mice to produce IgG anti-Dex antibodies. These findings suggest that the reduced capacity of conventionally raised BALB/c mice to mount an IgG response to the T-independent antigen Dex is due to a T cell-mediated suppressive mechanism which is neonatally induced by contact with environmental, i.e. bacterial, antigens. 相似文献