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Biomedical subjects

J Eichhorn

Publications and source records attributed to J Eichhorn.

At least 19 recordsLinked to original sources
PubMed2004

[Five hundred outpatient hernioplasties using the Lichtenstein method].

UNLABELLED: The Lichtenstein repair method is an excellent and simple technique for hernia repair performed as a day-case procedure. A consecutive series of 500 ambulatory groin hernia repairs from 1994 to 2002 was studied. The mean follow-up for 84.6% of the patients was 2 years (range 6-86 months). There were no severe complications. The rate of clinically important wound haematomas (n=6, 1.2%) was low, as well as the numbers of testicular atrophies (n=1, 0.2%) and deep wound infection (n=1, 0.2%). We saw no thrombosis. There were 15 recurrences (3.5%). Ninety-six per cent of the patients were satisfied with the outpatient operation. In day-case surgery, conditions for the patients' treatment at home should be checked carefully by surgeons before the operation. CONCLUSION: Our results suggest that the number of day-case hernia repairs can be increased without severe complications. The procedure can be performed on an outpatient basis without problems under general anaesthesia. Increasing day-case surgery could significantly reduce the costs of health care.

Adult↗
PubMed2004

Rings, slings and other vascular abnormalities. Ultrafast computed tomography and magnetic resonance angiography in pediatric cardiology.

Ultrafast CT and MR angiography are noninvasive, accurate and robust techniques for preoperative diagnosis and planning of congenital heart disease and vascular abnormalities in pediatric patients. While they seem to be equivalent to conventional catheter angiocardiography for detecting vascular abnormalities, they are more accurate for the diagnosis of potentially life-threatening complications, such as tracheal, bronchial or esophageal compression. The value of ultrafast CT and MR angiography is demonstrated in 22 pediatric patients with vascular rings, slings and other vascular abnormalities.

Angiography↗
PubMed2003

[Time-resolved multiphasic 3D MR angiography in the diagnosis of the pulmonary vascular system in children].

PURPOSE: To evaluate time-resolved, multiphasic 3D MR angiography (MRA) for the non-invasive assessment of the pulmonary vascular system in children. MATERIALS AND METHODS: 10 children aged 6 to 15 years (mean age 10 years) ware examined on a 1.5 T whole body MR system with time-resolved, multiphasic 3D MRA after injection of 0.2 mmol/kg body weight of Gd-DTPA. With the use of an ultrafast gradient echo pulse sequence with asymmetric k-space filling and very short echo and repetition times, a nominal spatial resolution of 1.4 x 1.4 x 2.0 mm3 could be achieved with a scan time of 5.6 and 6.2 seconds for a single 3D data set. Two radiologists, who were blinded to the clinical diagnosis, analyzed the image data in consensus. The image analysis included the assessment of the image contrast and artifacts as well as a quantitative analysis of the signal-to-noise (SNR) and contrast-to-noise ratios (CNR) for central and peripheral lung vessel segments. RESULTS: The children tolerated all examinations without any side effects. The referral diagnosis, which was based on echocardiography, catheter angiography and surgery, was confirmed by MRA in all cases. The image contrast was rated at least satisfactory in all but one case (19 of 20) and no artifacts were observed. The quantitative analysis of the SNR and CNR in the pulmonary arteries and veins confirmed the reader analysis of a high and uniform contrast throughout the entire pulmonary circulation. CONCLUSION: Time-resolved multiphasic 3D MRA allows a non-invasive diagnostic evaluation of the pulmonary circulation in children. In view of the excellent image quality, MRA may replace conventional diagnostic catheter angiography in the near future.

Adolescent↗
PubMed2001

Assessments of impacts of nitrogen deposition on beech forests: results from the Pan-European Monitoring Programme.

The article reviews effects of nitrogen (N) deposition on beech forest ecosystems in Europe. On the basis of beech plots of the Pan-European Monitoring Programme of ICP Forests and the EU, the deposition of N compounds as well as input-output budgets are listed and compared with studies in North America. The authors also discuss the critical threshold for N leaching. At present, N is leached in 10% of the plots evaluated. An in-depth evaluation of a beech plot in central Germany is presented. The high N leaching results in a considerable increase (four times higher N content in 2000 compared to 1965) in the export of nitrate from the beech forests from a nearby source. Finally, ecophysiological indicators (N content in beech leaves, fine root system, N content, root/shoot ratios) are discussed as a result of high N input.

Aluminum↗
PubMed2001

Insulin activates phospholipase C-gamma1 via a PI-3 kinase dependent mechanism in 3T3-L1 adipocytes.

Previously we have shown that the insulin receptor and phospholipase C-gamma1 physically interact in the 3T3-L1 adipocyte cell line. In this study, we investigated the ability of insulin and PDGF to stimulate PLC-gamma1 enzyme activity as measured by PI-(4,5)P(2) hydrolysis. Both insulin and PDGF caused a rapid (<1 min) increase in PLC activity associated with the respective receptor. PDGF treatment resulted in a higher and more sustained stimulation of PLC-gamma1 activity compared to insulin (0.95 pmol/min/mg vs 0.68 pmol/min/mg). Furthermore, insulin and PDGF promoted increases in total cellular DAG, one of the products of PI-(4,5)P(2) hydrolysis. Insulin-stimulated PLC activity appears to be downstream of PI-3Kinase as the DAG increase was partially blocked by Wortmannin and addition of PI-(3,4,5)P(3) activated PLC-gamma1 in vitro. Inhibition of PLC using U73122 or an inhibitory peptide caused a decrease in insulin-stimulated 2-deoxyglucose transport and GLUT4 translocation that was rescued by the addition of OAG, a cell-permeable synthetic DAG.

3T3 Cells↗
PubMed2001

Exploratory analysis and a stochastic model for humusdisintegration.

Ulrich (1981) supposes in the hypothesis of humusdisintegration that the balance between polymerisation and breakdown of organic material may be disturbed in chemically well buffered European forest soils. This new aspect of aluminium toxicity may cause nitrogen exceedance in forest ecosystems and subsequent seasonal nitrate output (Eichhorn and Hutterman, 1999). In a research program the substances in the seepage water are monitored in a small woodland in central Germany. We explore these multivariate data for examining possible influences on the process of humusdisintegration and its temporal evolution. As a result, a regression model for carbon is developed, which includes covariables, i.e., other substances, as well as spatial and temporal terms describing systematic variability. Especially iron and aluminium turn out to be very influential in the model. So far our work is a basic step for monitoring the seepage water data by means of stochastic modelling.

Aluminum↗
PubMed1999

Inhibition of PLC-gamma1 activity converts nerve growth factor from an anti-mitogenic to a mitogenic signal in CHO cells.

Nerve growth factor (NGF) treatment of Chinese hamster ovary fibroblast (CHO) cells exogenously expressing 2.5x105 TrkA receptors (CHO/TrkA) results in inhibition of serum and insulin-like growth factor-I (IGF-I) stimulated cell proliferation in a dose-dependent manner. Furthermore, NGF does not stimulate [3H]thymidine incorporation and inhibits IGF-I mediated DNA synthesis in CHO/TrkA cells. NGF and IGF-I induce extracellular-signal regulated kinase 1 (ERK1) and ERK2 activation, but NGF is able to stimulate a higher and more sustained activation of these enzymes compared with IGF-I. Cotreatment with NGF and IGF-I yields an ERK1/2 activity profile similar to that of NGF treatment alone. While pretreatment with mitogen activated protein kinase kinase (MKK) inhibitor PD98059 (30 microM) results in 100% inhibition of IGF-I stimulated MAPK phosphorylation (IC50<1 microM), NGF mediated MAPK phosphorylation is only decreased by 50% (IC50=3 microM). NGF, but not IGF-I, stimulates tyrosine phosphorylation and activation of PLC-gamma1 which can be inhibited in a dose-dependent manner by phosphoinositide-specific phospholipase C (PI-PLC) inhibitor U73122 (IC50=4 microM). Pretreatment with U73122 (IC50=7 microM) results in an 87% inhibition of NGF mediated MAPK phosphorylation, while cotreatment with PD98059 and U73122 results in 97% inhibition. U73122 pretreatment has no effect on NGF stimulated Akt activation. NGF, but not IGF-I, stimulates the tyrosine phosphorylation of Suc1-associated neurotrophic factor-induced tyrosine phosphorylation target (SNT-1)/fibroblast growth factor receptor substrate 2 (FRS2) which can be completely prevented by pretreatment with 10 microM U73122. Finally, inhibition of PI-PLC results in NGF's ability to stimulate DNA synthesis in the absence and presence of IGF-I.

Adaptor Proteins, Signal Transducing↗
PubMed1998

Association of the insulin receptor with phospholipase C-gamma (PLCgamma) in 3T3-L1 adipocytes suggests a role for PLCgamma in metabolic signaling by insulin.

Phospholipase C-gamma (PLCgamma) is the isozyme of PLC phosphorylated by multiple tyrosine kinases including epidermal growth factor, platelet-derived growth factor, nerve growth factor receptors, and nonreceptor tyrosine kinases. In this paper, we present evidence for the association of the insulin receptor (IR) with PLCgamma. Precipitation of the IR with glutathione S-transferase fusion proteins derived from PLCgamma and coimmunoprecipitation of the IR and PLCgamma were observed in 3T3-L1 adipocytes. To determine the functional significance of the interaction of PLCgamma and the IR, we used a specific inhibitor of PLC, U73122, or microinjection of SH2 domain glutathione S-transferase fusion proteins derived from PLCgamma to block insulin-stimulated GLUT4 translocation. We demonstrate inhibition of 2-deoxyglucose uptake in isolated primary rat adipocytes and 3T3-L1 adipocytes pretreated with U73122. Antilipolytic effect of insulin in 3T3-L1 adipocytes is unaffected by U73122. U73122 selectively inhibits mitogen-activated protein kinase, leaving the Akt and p70 S6 kinase pathways unperturbed. We conclude that PLCgamma is an active participant in metabolic and perhaps mitogenic signaling by the insulin receptor in 3T3-L1 adipocytes.

3T3 Cells↗
PubMed1998

Noninvasive biomagnetic imaging in coronary artery disease based on individual current density maps of the heart.

OBJECTIVE: In this paper we present an attempt at noninvasive imaging of distributed myocardial electrical activity in patients suffering from myocardial infarction and in healthy subjects. Although advances have been made, noninvasive three-dimensional imaging of cardiac electrophysiological activity is still in its infancy and extending our knowledge of cardiac electrophysiological properties may be a valuable guide in the treatment of patients with coronary artery disease. METHODS: Magnetic field mapping data formed the input for an inverse solution that is based on a multiple dipole model. The lead field normalized minimum norm least square criterion was applied to predefined myocardial source geometry. Current density distributions were calculated for the left ventricle during ventricular depolarization. Images from two patients with previous myocardial infarction were compared to images from two healthy subjects. RESULTS: Low regional and global current density was found in the infarction patients. Regions of low current density corresponded to infarcted segments. The images of the healthy subjects displayed less marked areas of low current density. CONCLUSION: The proposed multiple dipole model may be able to distinguish viable from scarred myocardium. A prospective clinical study should be undertaken to investigate the spatial resolution and the diagnostic performance of this method.

Body Surface Potential Mapping↗
PubMed1998

Antiendothelial cell antibodies in thromboangiitis obliterans.

The occurrence of autoimmune phenomena in 28 patients with thromboangiitis obliterans (Buerger's disease) was determined. The following were sought: antineutrophil cytoplasmic antibodies against proteinase 3 (cANCA) and myeloperoxidase (pANCA), antinuclear antibodies, anti-Ro antibodies, anticardiolipin antibodies, and antiendothelial cell antibodies (AECA). For the last, an enzyme-linked immunosorbent assay was developed which verified the presence of the AECA phenomenon with immunofluorescence and confocal microscopy. Seven patients with active disease had AECA titers of 1,857 +/- 450 arbitrary units (AU) compared with 126 +/- 15 AU in 30 normal control subjects (P < 0.001) and 461 +/- 41 AU in 21 patients in remission (P < 0.01). Antibodies from the sera of patients with active disease reacted not only with surface epitopes but also with sites within the cytoplasm of human endothelial cells. AECA may be useful in following disease activity and may play a role in the pathogenesis of thromboangiitis obliterans.

Adult↗
PubMed1997

Endothelial adhesion molecules and leukocyte integrins in preeclamptic patients.

Endothelial cell activation is important in the pathogenesis of preeclampsia; however, the nature of the activation is unknown. We investigated 22 patients with preeclampsia. 29 normotensive pregnancies, and 18 nonpregnant women to test the hypothesis that serum from preeclamptic patients induces expression of intercellular adhesion molecule-1 (ICAM-1) and vascular adhesion molecule-1 (VCAM-1) and stimulates intracellular free calcium concentrations [Ca2+]i in cultured endothelial cells. We then asked whether the corresponding integrin adhesive counter receptors lymphocyte function-associated antigen-1 (CD11a/CD18), macrophage-1 antigen (CD11b/CD18), p150,95 (CD11c/CD18), and very late activation antigen-4 (CD49/CD29) are increased in patients with preeclampsia. In the pregnant women, the measurements were conducted both before and after delivery. Integrin expression was measured by fluorescent antibody cell sorting analysis using monoclonal antibodies. ICAM-1 and VCAM-1 were analyzed on endothelial cells by enzyme-linked immunosorbent assay. [Ca2+]i was measured with fura 2. Serum from preeclamptic patients increased endothelial cell ICAM-1 expression but not VCAM-1 expression. Preeclamptic patients' serum also increased [Ca2+]i in endothelial cells compared with serum from normal nonpregnant or normal pregnant women. Endothelial cell [Ca2+]i concentrations were correlated with the ICAM-1 expression in preeclamptic patients (r = .80, P < .001) before but not after delivery. Expression of the integrin counter receptors on leukocytes was similarly increased in preclampsia and normal pregnancy compared with the nonpregnant state. The expression decreased significantly after delivery in both groups. Our results demonstrate that serum from preeclamptic women induces increased ICAM-1 surface expression on endothelial cells, while the expression of the integrin counterreceptors was not different. The effect on endothelial cells may be related to an increase in [Ca2+]i. The effect on cultured endothelial cells and the rapid decrease after delivery suggests the presence of a circulating serum factor which increases endothelial cell [Ca2+]i and enhances adhesion molecule expression.

Adult↗
PubMed1996

Anti-endothelial cell antibodies in Takayasu arteritis.

BACKGROUND: Although a specific etiology for Takayasu arteritis has not been found, the bulk of evidence favors an autoimmune mechanism. We examined the sera of 19 patients with Takayasu arteritis for antineutrophil cytoplasmic antibodies (ANCA), antinuclear antibodies (ANA), anti-DNA antibodies, antibodies to extractable nuclear antigens (ENA), anti-Ro anti-bodies, anticardiolipin antibodies, circulating immune complexes, and anti-endothelial cell antibodies (AECA). METHODS AND RESULTS: We used enzyme-linked immunoassays, immunofluorescence, counterimmunoelectrophoresis, fluorescent-activated cell sorter (FACS) analysis, and confocal microscopy. We found that although no patient had positive ANCA, ANA, anti-DNA antibodies, ENA antibodies, anti-Ro antibodies, or anticardiolipin antibodies, 18 of the 19 patients had AECA. The AECA titers of the patients were 2561 +/- 1458 compared with 126 +/- 15 arbitrary units in a normal group of control subjects (P < .001). To verify the specificity of AECA, we performed cytofluorimetry on human endothelial cells with the sera from patients and control subjects. Two entirely separate patterns of fluorescence intensity were identified. We next performed immunocytochemistry and confocal microscopy with human endothelial cells subjected to patients' sera and to sera from normal subjects. The cells subjected to sera from patients with Takayasu arteritis demonstrated specific immunofluorescent staining of their plasma membrane and cytosol. CONCLUSIONS: AECA are frequently present in patients with Takayasu arteritis. They may play a role in the pathogenesis. Furthermore, they may be useful as an additional diagnostic tool.

Adolescent↗
PubMed1996

Disease activity and autoantibodies to endothelial cells in patients with Wegener's granulomatosis.

The purpose of this study was to assess the utility of antiendothelial cell antibodies (AECAs) in patients with active and inactive Wegener's granulomatosis. We studied 32 patients with Wegener's disease (clinical criteria and biopsy, as well as titers of antineutrophil cytoplasmic antibodies with a cytoplasmic pattern [cANCA]) over 4 years and compared their AECA values with those of 24 normal subjects similar in age and gender distribution, as well as with those of patients with chronic glomerulonephritis with or without dialysis and of patients with severe arteriosclerosis. We measured AECAs, cANCAs, C-reactive protein, erythrocyte sedimentation rate, proteinuria, and renal function in patients with active disease or in patients reactivating their disease. A time course with repeated AECAs was conducted over 27 months in 24 patients. The AECAs were measured with an enzyme-linked immunosorbent assay. The specificity was verified with immunofluorescent confocal microscopy, which showed the AECA epitopes to be within the cytoplasm of endothelial cells. Elevated AECA titers were found in all patients with active disease, not all of whom had positive cANCAs. Although elevated AECAs were also found in some patients with inactive disease, normal AECA values were seen only in patients with inactive disease. Patients with active disease entering remission showed a decrease in AECA titers, while patients entering a relapse increased their AECA titers. We conclude that AECAs are present in patients with Wegener's granulomatosis. To our knowledge, these are the first serial AECA observations. Our data suggest that AECAs are correlated with disease activity. Antiendothelial cell antibody values in the normal range strongly support remission. These findings may be of clinical utility in distinguishing relapse from concomitant illness.

Autoantibodies↗