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Biomedical subjects

I Lehmann

Publications and source records attributed to I Lehmann.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cloning of bovine RANTES mRNA and its expression and regulation in ovaries in the periovulatory period.

RANTES may be one of the chemoattractants involved in stimulating eosinophils and macrophages to migrate selectively into bovine dominant follicles and into developing corpora lutea. We sequenced a 736 bp fragment of the bovine RANTES mRNA encoding the complete protein and defined the ovarian source of RANTES mRNA. As demonstrated by competitive RT-PCR, follicle-derived macrophages showed a 100-1000 times higher RANTES mRNA level compared to unpurified granulosa cells or follicle-derived fibroblasts. By means of in situ hybridization, RANTES mRNA positive macrophages were located in the former thecal layer of the developing corpora lutea.

Amino Acid Sequence↗
PubMed1998

Levels of chlordane compounds in fish muscle, -meal, -oil and -feed.

Cis-, trans-, oxychlordane and trans-nonachlor were determined in the edible part of more than 140 fish samples of 15 different species and in fish meal, -oil and fish feed. The investigated fish included most of the important fish species consumed in Germany. Highest concentrations were found in muscle of marine fish with high or moderate fat content, but also in eel and farmed salmon. Marine fish with low fat content contained only traces of chlordane in the muscle tissue. A relationship between fishing ground and levels of chlordane could not be established. Contamination level of herring was related to the age (length) of the fish. Data are also given for contamination levels of fish meal, -oil and -feed.

Animal Feed↗
PubMed1997

Effect of gamma-interferon on binding of gliadin and other food peptides to the human intestinal cell line HT-29.

gamma-Interferon is one of the main cytokines released during activation of intestinal lymphocytes in coeliac patients. The question has never been addressed whether gamma-interferon influences binding of gliadin and other food peptides to human enterocytes. Therefore, the human intestinal epithelial cell line HT-29 was cultured with gliadin, casein, beta-lactoglobulin and ovalbumin, with or without gamma-interferon, and peptide binding to cells was determined by flow cytometry and fluorescence microscopy. gamma-Interferon stimulated gliadin binding by a factor of 4. Binding was saturable with half maximal binding at 0.15 mg/ml. For maximal binding, an incubation of at least 24 h was necessary. gamma-Interferon increased binding of beta-lactoglobulin and casein, too, but inhibited that of ovalbumin. Binding of gliadin was inhibited by the other peptides. Under the conditions of ongoing mucosal inflammatory reactions and release of gamma-interferon, enhanced binding may trigger intestinal lymphocytes, increase secretion of cytokines and thus induce a vicious circle.

Caseins↗
PubMed1997

CD97: a dedifferentiation marker in human thyroid carcinomas.

CD97 is a dimeric glycoprotein of Mr 75,000-85,000 and 28,000 belonging to a novel subfamily of seven-span transmembrane region leukocyte cell surface molecules. It is expressed abundantly in cells of hematopoietic origin. This is the first report demonstrating the expression of CD97 outside the hematopoetic system. CD97 was studied in normal human and neoplastic follicular epithelium of the thyroid and anaplastic (n = 3) and papillary (n = 1) thyroid carcinoma cell lines. In normal thyroid tissue (n = 11), no immunoreactivity of CD97 could be found, whereas in differentiated thyroid carcinomas (n = 10), CD97 expression was either lacking or low. Eleven of 12 undifferentiated anaplastic carcinomas revealed high CD97 presentation. CD97 was absent or only weakly present in patients with postoperative T1 tumors but increased greatly with the progression to postoperative T4 tumors. CD97 is clearly present in thyroid carcinoma cell lines but only at a very low level in normal human thyrocytes. Quantitation of CD97 cell surface expression levels revealed that C 643 and SW 1736 cells showed a two to four times higher specific antibody-binding capacity than did 8505 C and HTh 74 cells and a nearly 20 times higher specific antibody-binding capacity than normal thyrocytes. Phorbol 12-myristate 13-acetate treatment progressively caused a decrease of CD97 antigen expression in all cell lines to about 30% of their initial levels after 48 h. Immunohistochemical staining of SW 1736 cells revealed that CD97 is located in most of the cell compartments and suggested a CD97 internalization process after phorbol 12-myristate 13-acetate treatment. Semiquantitative reverse transcription-PCR showed a correlation of CD97 mRNA and cell surface CD97 expression level in the cell lines. SW 1736, HTh 74, and 8505 C cells apparently expressed CD97 with alternative glycosylation compared to peripheral lymphocytes, whereas most of the CD97 antigen presented on thyrocytes and C 643 cells had glycosylation sites resembling those of lymphocytes. The data suggest that CD97 expression may be a sensitive marker of dedifferentiation and of lymph node involvement in human thyroid tumors.

Antibodies, Monoclonal↗
PubMed1996

Expression of tumour necrosis factor-alpha (TNF-alpha) mRNA and protein in pathological thyroid tissue and carcinoma cell lines.

There has been much controversy about the presence of TNF-alpha within thyroid tissue. We therefore conducted a study to determine if TNF-alpha mRNA is present in thyroid tissue and thyroid-derived cells. Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was employed with a heterologous competitor fragment. Significantly lower levels of TNF-alpha mRNA were found in the autonomous nodules from patients with thyroid autonomy (TA; n = 4; 5.7 +/- 1.3 arbitrary units (AU) (mean +/- s.e.m.); P < 0.03) and in normal thyroid tissue (n = 2, 7.0 +/- 3.1 AU) compared with tissue from patients with Graves' disease (GD; n = 13; 27.9 +/- 10.3 AU), non-toxic multinodular goitre (NTG; n = 5; 20.9 +/- 5.8 AU) and perinodular tissue from TA patients (20.3 +/- 4.0 AU). Higher levels were detected in tissues from patients with Hashimoto's thyroiditis (HT; n = 2; 51.3 +/- 10.3 AU). Cultures of pure thyroid-derived fibroblasts (46 +/- 18 AU thyrocytes (33 +/- 8 AU), and the anaplastic thyroid carcinoma cell lines 8505 C (39 +/- 11 AU), SW 1736 (214 +/- 16 AU) and C643 (3 +/- 1 AU) showed significantly lower TNF-alpha mRNA levels than thyroid-derived lymphocytes (1650 +/- 32 AU). TNF-alpha was detected in the supernatants of unstimulated lymphocytes (22.1 +/- 1.1 pg/ml) and SW 1736 cells (3.5 +/- 0.9 pg/ml), but not in unstimulated fibroblasts and thyrocytes. Using an intracellular labelling technique in flow cytometry, the immunophenotype of stimulated TNF-alpha-positive lymphocytes was determined as predominantly CD3+CD45RO+. Our results suggest that TNF-alpha is present in the thyroid tissue of different thyroid disorders. Thyroid-derived lymphocytes are potential TNF-alpha producers and may thus locally influence thyroid function.

Adult↗
PubMed1996

Different immunophenotype and autoantibody production by peripheral blood and thyroid-derived lymphocytes in patients with Graves' disease.

Direct multi-colour flow cytometric analysis was employed in patients with Graves' disease (n = 10) to determine the immunophenotype in peripheral blood lymphocytes (PBL) at the time of diagnosis without treatment (PBLw) and prior to operation (PBLp) and in thyroid-derived lymphocytes (TL). Additionally, the secretion of anti-thyroperoxidase antibodies (anti-TPO) was measured during culture of isolated peripheral or thyroid-derived B cells. Among TL from patients with high serum levels of anti-TPO (6/10) a significantly (p < 0.01) higher percentage of B cells were detected compared to PBLp (TL: 21.7 +/- 7.2%; PBLp: 13.2 +/- 4.5%). Enriched thyroid-derived B cells only from these patients also showed high spontaneous anti-TPO secretion during culture. The difference between peripheral and thyroid-derived natural killer (NK) cells was highly significant (p < 0.001; TL: 5.6 +/- 6.3%; PBLp: 13.6 +/- 5.5%). Two patients were found with a higher number of NK cells within TL. These patients were among those who had a low number of B cells infiltrating the thyroid gland. Regarding the expression of several other differentiation antigens, i.e. CD4 and CD8, gamma/delta TCR bearing T cells and CD45R0 on CD4+ T cells as a marker for memory cells, on TL no differences could be detected between patients with or without anti-TPO. In TL 31.5 +/- 7.7% of CD3- cells expressed the HLA-DR antigen (vs. 6.1 +/- 2.4% in PBLp; p < 0.001). Half of these cells simultaneously expressed the activation antigen CD69. Surprisingly, the number of CD3+ TL bearing the IL-2 receptor (CD25) and transferrin receptor (CD71) was not increased. Taken together, the proportional distribution of B and NK cells within the thyroid correlates with the anti-TPO secretion in vivo and in vitro, suggesting different immune response regulation processes of TL.

Adult↗
PubMed1996

Activated and interferon-gamma producing thyroid-derived T cells are detected in Graves' disease, thyroid autonomy as well as in non-toxic multinodular goiter.

The relative numbers of activated and interferon gamma (IFN-gamma)-producing peripheral blood lymphocytes (PBL) and thyroid-derived lymphocytes (TL) were determined using double surface and intracellular labeling techniques in flow cytometry. Cells were analyzed from 10 patients with Graves' disease (GD), eight patients with thyroid autonomy (TA) and five patients with non-toxic multinodular goiter (NTG). A maximum of 1% IFN-gamma+ cells were detected both in unstimulated PBL and TL. Stimulation caused a two- to threefold higher number of IFN-gamma+ cells in TL (GD, 48 +/- 12%; TA, 48 +/- 11%; NTG, 50 +/- 15%) as compared to PBL (GD, 15 +/- 7%; TA, 16 +/- 8%, NTG, 18 +/- 10%) of the same patients. Nearly all IFN-gamma+ TL in GD were CD3+ T cells, whereas 10-20% of IFN-gamma+ TL in TA and NTG were NK cells. In PBL 80% and in TL almost 100% of IFN-gamma+ cells were antigen-primed CD45RO+ cells. Only 25-35% of IFN-gamma+ thyroid-derived T cells expressed the CD4 antigen. About 42 +/- 10% thyroid-derived T cells in GD, 33 +/- 11% in TA and 34 +/- 13% in NTG expressed the HLA-DR molecule but not the interleukin 2 (CD25) or the transferrin receptor (CD71). Forty per cent of these HLA-DR+ T cells showed an intracellular staining for IFN-gamma and half of them co-expressed the activation antigen CD69. Immunofluorescence double labeling on thyroid cryostat sections demonstrated that HLA-DR+ T cells were also present in situ. The presence of activation antigens on thyroid-derived T cells not only in patients with GD but also in TA and NTG suggests failsafe mechanisms such as anergy, suppression or cytokine regulation in so-called non-immunogenic goiter.

Adult↗
PubMed1995

Effect of gliadin and other food peptides on expression of MHC class II molecules by HT-29 cells.

Expression of major histocompatibility (MHC) class II molecules by enterocytes is known to be enhanced in coeliac disease and other disorders characterised by intestinal inflammation--an effect thought to be mediated via intestinal lymphocytes. To investigate if food peptides can exert direct effects on class II expression, the influence of gliadins, casein, and beta lactoglobulin on an intestinal epithelial cell line (HT-29) was examined in the absence of immune cells. Class II expression was determined by flow cytometry and immunofluorescence microscopy using antibodies against the beta chain of all products of the gene subregions DR, DQ, and DP. MHC expression was low in HT-29 cells but could be stimulated by interferon gamma. Tryptin digested gliadin had no effect on class II expression. In the presence of interferon gamma, however, it was able to amplify MHC class II expression to mean (SEM) 150 (4)%. Casein exerted a similar effect (160 (14)%), but undigested gliadin, tryptin digested casein, and beta lactoglobulin had no influence. The observations suggest that within the concert of cytokine mediated interactions between enterocytes and lymphocytes, some dietary peptides could upregulate the presentation of food antigens, leading to a more efficient stimulation of lymphocytes, which in the case of coeliac disease might result in damage to the enterocytes.

Adenocarcinoma↗
PubMed1993

Organochlorine residues in the edible part of eels of different origins.

Fifty-four eel samples from 11 different countries were analysed by capillary gas chromatography for levels of the pesticides aldrin, endrin, hexachlorobenzene, alpha- and beta-BHC, lindane, heptachlor, octachlorostyrene, pp'-DDT, pp'-DDD, pp'-DDE, and for the levels of the PCB congeners 28, 52, 101, 138, 153, and 180. Wild eels, especially from the Baltic Sea area, had elevated contents compared to farmed eels. The mean contamination level reached only 1-5% of the allowable values given by German directives and never exceeded the official limits.

Animals↗
PubMed1988

Enzyme pattern and lipid peroxides in endomyocardial biopsies from patients with cardiomyopathy and myocarditis.

Methods have been developed for measuring several biochemical parameters (isoenzymes of LDH and ASAT, glycogen phosphorylase, lipid peroxides) in extremely small tissue samples (0.2-1.8 mg) taken using a left ventricular biopsy technique. Endomyocardial biopsies from patients with dilative and hypertrophic cardiomyopathy (CMP) and with myocarditis were investigated and compared with a reference group without actual functional and morphological evidence of chronic heart disease. Patients with myocarditis showed the highest activities of LDH and its isoenzymes, ASAT, ASATm and glycogen phosphorylase and the highest concentration of lipid peroxides. In patients with hypertrophic CMP increased activities of glycogen phosphorylase and decreased activities of ASAT and ASATm have been found. In patients with dilative CMP slightly elevated ASAT and ASATm activities have been observed. The results obtained in this study suggest that the parameters investigated could be useful in differentiating between cardiomyopathies and myocarditis.

Adult↗
PubMed1987

Enzyme pattern in endomyocardial biopsies from patients with chronic heart diseases.

In endomyocardial biopsies from 67 patients with various chronic heart diseases (small vessel disease, cardiomyopathies and hypertensive heart disease) the isoenzymes of Lactate Dehydrogenase (LDH) and Aspartate Aminotransferase (ASAT) and Glycogen Phosphorylase (GP) were investigated and compared with a reference group without actual morphological and functional evidence of chronic heart disease. The analyzed parameters showed characteristical alterations dependent on the degree of hypertrophy of the heart muscle cells and the stage of the disease as assessed by left ventricular enddiastolic pressure (LVEDP), ventricular kinetics, left ventricular heart mass (LVHM) and exercise electrocardiogram. The biochemical alterations found reflect different metabolic situations in the myocardium and could be useful as additional information for assessing the severity of the disease.

Adult↗
PubMed1982

Electrically induced tachyarrhythmia and the effect of propranolol on the release of cyclic AMP and prostaglandin E by the canine left ventricle.

In anesthetized open-chest dogs, tachyarrhythmia (TA) was electrically induced by above-threshold stimuli via the right ventricle. During TA, a significant increase in the release of PGE and cAMP was observed in the canine coronary sinus blood (CSB). The efflux of cAMP corresponded with a concomitant increase in the left ventricular tissue level of this nucleotide. Pretreatment with propranolol (1.0 mg/kg i.v.) prevented the TA-induced changes in the level of PGE as well as cAMP in the CSB and in the tissue levels of cAMP. There was an increase in the activity of phosphorylase a in the myocardial tissue during TA which could be abolished by propranolol pretreatment. These results suggest possible interrelationships among catecholamines, cAMP, and PGE.

Animals↗
PubMed1977

[Pre-, intra- and postoperative behavior of LDH and GOT isoenzymes in the plasma of patients with chronic ischemic heart disease].

The isoenzymes of LDH (types H and M) and the isoenzymes of GOT (cytoplasma, mitochondria) were examined in 14 male patients with chronic ischaemic heart disease before, during and after operation. The present study compares them with clinical parameters. Considering the combination of the two isoenzyme ratios, it can be generalized that chronic ischaemia of the heart is characterized both by a decrease of the ratio H : M of the LDH and an increase of the ratio M : C of the LDH and an increase of the ratio M : C of the GOT. Confirming the function of the open by-pass by recoronarography, the isoenzyme values are normal both with regard to their ratio and to their absolute values.

Adult↗