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Biomedical subjects

L Jäger

Publications and source records attributed to L Jäger.

At least 73 records · Page 4Linked to original sources
PubMed1995

[Vascular, inflammatory and tumorous lesions of the temporal bone and cerebellopontile angle: applications of magnetic resonance tomography].

Advances in high resolution magnetic resonance imaging (MRI) allow the evaluation of the cerebellopontine angle and temporal bone. The purpose of our study was to demonstrate pathological and anatomical aberrations of cerebral arteries in relation to clinical symptoms. The study was carried out on a 1T MR whole body scanner (Impact, Siemens, Erlangen, Germany), using a head coil, a pre- and postcontrast ("Magnevist", Schering, Berlin, Germany) T1-weighted 2D-FLASH sequence and a T2-weighted turbo-spin echo sequence. We examined 22 patients suffering from asymmetric hearing loss, pulse-synchronous tinnitus, hemifacial spasm or facial palsy. The problem of a clear differentiation of meningiomas and acoustic neurinomas by means of MRI is discussed. We identified aberrant AICAs at the cerebellopontine angle in close contact with the V., VII. and VIII. cranial nerve. Inflammatory lesions of the facial and vestibulocochlear nerve were visualised successfully. The potential of the pre- and postcontrast 2D-FLASH sequence for the detection of a wide range of different lesions in the cerebellopontine angle and the temporal bone in MRI of the head was demonstrated.

Arteries↗
PubMed1995

[Sarcoma of the nose and paranasal sinuses].

Sarcomas of the head and neck are rare tumours accounting for less than 1% of all malignant neoplasms in this region. The prognosis of these tumours and the survival in adults (< 50% at 5 years) is directly related to histological tumour type, tumour size and the possibility of adequate tumour resection. In the present paper, the authors present the course of sarcomas with special reference to rhabdomyosarcoma and osteosarcoma in the nose and paranasal sinuses. Surgical resection with pathologically free margins represents the best modality of initial therapy. Additional adjuvant radiotherapy and/or chemotherapy have shown better survival rates in pediatric patients and, to some degree, also in adults. The purpose of future studies should be the development of new therapy protocols which could further elucidate the beneficial effects of adjuvant therapy in the treatment of sarcomas of the head and neck.

Adolescent↗
PubMed1995

[Pulsatile tinnitus as a key symptom of glomus tumor: diagnostic value of magnetic resonance tomography].

The aim of this study was to evaluate the diagnostic value of modern imaging tools in pulsatile tinnitus, which might be apparent in a variety of different diseases. While computed tomography (CT) and digital subtraction angiography (DSA) have been the methods of choice in the diagnostic management of this symptom and its related diseases, the technical progress in the development of MRI and MRA highly recommends these techniques as additional yet sufficient imaging tools. The authors demonstrate 2 representative cases of pulsatile tinnitus (one patient with glomus tumour, one patient with jugular bulb deformity) and the adequate diagnostic procedure in terms of imaging tools. It is concluded that a routine MRI-examination might allow a diagnosis with high sensitivity and specificity. Still, digital subtraction angiography and computed tomography remain indispensable in the diagnostic management of pulsatile tinnitus.

Adult↗
PubMed1995

Optimization of apple allergen preparation for in vivo and in vitro diagnostics.

The aim of our investigation was to obtain a well-characterized active apple extract suitable for both in vivo and in vitro diagnostics by a technically simple method. For this purpose, apple extracts were prepared by homogenization in potassium phosphate buffer or by precipitation in organic solvents and resolubilization in potassium phosphate buffer in the presence or in the absence of enzyme inhibitors. These extracts were comparatively investigated by means of SDS-PAGE, two-dimensional electrophoresis, immunoblotting, RAST inhibition, and prick test. The in vitro investigations indicated that extracts prepared by precipitation in organic solvents (diacetone alcohol) at -20 degrees C have a higher allergen activity than those prepared by extraction in aqueous solutions. From the in vivo tests (prick test), it was concluded that application of inhibitors of cytoplasmic enzymes (phenol oxidases, peroxidases, proteases) already during extraction is an essential precondition for active prick test solutions. Correspondingly, the extract obtained by solvent precipitation in the presence of enzyme inhibitors appeared to be most suitable for clinical application.

Allergens↗
PubMed1995

Investigation of the stability of apple allergen extracts.

To determine optimal conditions for allergen preservation, we investigated the influence of different stabilizing additives and of storage temperature on the allergen activity of apple protein preparations, obtained by extraction in phosphate buffer or by precipitation in diacetone alcohol and resolubilization in phosphate buffer in the presence or absence of enzyme inhibitors. For this purpose, the extracts were stored for 6 months either in frozen state at -20 degrees C or in lyophilized state at -20 degrees C, 4 degrees C, or room temperature and were characterized by SDS-PAGE, immunoblot, ELISA inhibition, and prick test. The highest stability revealed the extracts that were prepared by precipitation in the organic solvent in the presence of enzyme inhibitors, lyophilized, and stored at -20 degrees C. For storage of extract solutions at 4 degrees C, PBS/glycerol and cysteine/sodium citrate/glycerol were found to be the most effective stabilizing additives.

Allergens↗
PubMed1995

Purification and characterization of the major allergen from apple and its allergenic cross-reactivity with Bet v 1.

The major allergen from apple extract was concentrated by anion exchange chromatography and further purified by reverse-phase HPLC. A distinct peak with a high degree of homogeneity was obtained. The isolated protein has a MW of 18 kD and specific IgE-binding capacity (immunoblotting, IgE-binding inhibition). N-terminal amino acid analyses of the allergen allowed 37 cleavages and showed 67.6% identity to Bet v 1, the major allergen of birch pollen. Enzyme immunoassay inhibition studies with serum of birch/apple-allergic patients showed that besides cross-reacting structures to Bet v 1, apple-specific IgE antibodies could exist. Monoclonal antibodies (mAbs) were raised against the 18-kD allergen from apple and characterized by means of immunoblotting and ELISA. Only three of the eight studied mAbs reacted with Bet v 1.

Allergens↗
PubMed1995

[Primary culture of different renal cell carcinoma cells with respect to immunomodulatory effects].

The presented results show that renal cell carcinomas (RCC) have partial immunomodulatory capacity (production of cytokines as IL-6, -10, -11; modulation of mitogen-induced transformation of T lymphocytes). The production of IL-10 shows a tendency to correlate with higher staging and grading of RCC. The cytokine production does not correlate with specific types of RCC. Direct immunosuppression of T lymphocytes in lymphocyte transformation tests (LTT) was not detectable.

Carcinoma, Renal Cell↗
PubMed1994

A two-site monoclonal antibody ELISA for the quantification of group V allergens in grass extracts.

A two-site solid-phase enzymimmunoassay was used for the quantification of group V allergen in grass pollen extracts in mass units. The assay is based on the monoclonal antibodies (MoAbs), 1D11 and 3B2 which recognize different epitopes on the standard Phl p V. The MoAb-ELISA is very sensitive (15-100 ng/ml Phl p V) and highly specific for group V allergens. Six pollen extracts of different grasses demonstrated parallel binding curves. The group V content ranged between 73 and 673 micrograms/ml in the extracts. The International Standard of Phleum pratense (IS 82/520) contains 400 micrograms/ml Phl p V. A good correlation was observed between the group V content and RAST inhibition, with the exception of Poa pratensis.

Allergens↗
PubMed1994

Analysis of human T cell clones reactive with group V grass pollen allergens.

Twenty-seven T cell clones (TCC) reactive with group V allergens of Phleum pratense (Phlp V) were established from the peripheral blood of 3 patients allergic to grass pollen. Twenty-four TCC showed the helper cell phenotype CD3+, CD4+, CD8-; the remaining clones were CD3+CD4-CD8+. T cell recognition of Phlp V was exclusively HLA-DR restricted. Many of the Phlp V reactive TCC (19 of 27; 70%) were stimulated additionally by other group V allergens isolated from Lolium perenne, Poa pratensis, and Dactylis glomerata. These data indicate the existence of cross-reacting T cell epitopes among group V allergens of different grasses. The Phlp V triggered cytokine production demonstrated in 13 out of 24 CD4+ TCC a Th2-like pattern (high interleukin 4/gamma-interferon ratios) suggesting group V allergens as important targets of grass pollen specific IgE.

Adult↗
PubMed1993

In patients with common variable immunodeficiency, interleukin-6 and expression of its receptor on B-cells are normal.

In a group of patients suffering from common variable immunodeficiency (CVID), levels of interleukin-6 (IL6) were measured and found to be in the normal range or even increased, for single patients. IL6 production of peripheral blood mononuclear cells was shown to be in the normal range when corrected for monocyte number. To exclude the possibility that the Interleukin-6 receptor (IL6R) on B-cells is missing, its expression was measured by assessing the binding of a Phycoerythrin-derivative of IL6 by flow cytometry and correlated with various markers for B-cells and T-cells. As compared with normal controls, no statistically significant deviation of the group as a whole nor for individual patients could be shown. It was concluded that lack of B cell differentiation in the presence of normal to high IL6 as shown for these patients is not due to inability of the B cells to detect IL6 in the serum.

Antigens, CD↗
PubMed1993

Monoclonal antibody immunoassay for quantitative analysis of group V allergens in grass pollen extracts.

A two-site monoclonal antibody (MoAb) ELISA has been developed for the quantification of the Phleum pratense major allergen, Phl p V. The assay is based on two MoAbs which recognize different non-overlapping epitopes on the Phl p V molecule; one antibody (1D11) was immobilized on the solid phase and the other (3B2) was biotinylated. An affinity-purified Phl p V preparation (purity of 95%) was used as standard. The assay has a sensitivity of 10 ng/ml of allergen and is suitable for the detection of group V allergen in aqueous grass extracts. The specificity of the assay was investigated with 14 grass pollen and five non-grass pollen extracts. Different levels of group V allergen were detected in extracts of grasses, but not in non-grasses. The assay gives a good correspondence with allergenic activity of extracts as determined by ELISA inhibition using serum pool of allergic patients. The results indicate that the two-site MoAb ELISA could be very useful in the standardization of allergenic extracts from grass pollen.

Allergens↗
PubMed1993

Detection of crossreactive determinants in grass pollen extracts using monoclonal antibodies against group IV and group V allergens.

Monoclonal antibodies (MoAb) to defined allergens of P. pratense were raised. Five of them were selected for detailed studies by means of immunoblotting after SDS-PAGE and IEF of extracts from P. pratense and L. perenne. Three antibodies (1D11, 3B2, 2D1) recognize structures with mol. wt of 29 and 34 kD and pI of 4.8-7.6, corresponding to group V allergens. Two other MoAbs (2D8, 3C4) are directed against strong basic structures with a mol. wt of 50 kD and pI of 7.8-9.5 according to group IV allergens. The specificity of antibodies was supported by direct ELISA with purified group V and IV allergens. The isolated allergens were characterized before by SDS-PAGE and CIE and that allergenicity was detected with sera of patients with allergic rhinitis. Using our selected MoAbs crossreactive epitopes on group V and IV allergens have been excluded. Our antibodies have been used to detect crossreactivity in 14 grass pollen extracts. The evaluation of the pollen extracts has been performed by enzyme immunoassay (EIA) inhibition. One MoAb (3C4) is able to recognize group IV allergens in all grass species analysed whereas the MoAb 2D8 seems to identify group IV structures in selected grasses only. Binding to conserved structures of group V has been proved for MoAb 1D11. Other group V specific MoAbs (2D1, 3B2) identify similar, however incomplete, spectra. These results have been confirmed also by the dot immunobinding assay.

Allergens↗
PubMed1993

Characterization of murine monoclonal antibodies to phospholipase A2 and mellitin from bee venom.

9 murine monoclonal antibodies (MoAbs), 7 to phospholipase A2 (Pla2; Api m I) and two to mellitin (Api m III) have been produced. Specificities were demonstrated using immunoblotting and enzyme immunoassays (ELISA). Antibodies specific for Pla2 were characterized in detail. Epitope mapping of Pla2-specific MoAbs identified three independent binding regions. 5 selected MoAbs bound to one of these sites compete with specific human IgE. Two of MoAbs characterized are suitable tools to quantify Pla2 in a two-site binding assay.

Animals↗
PubMed1993

[IgE rheumatoid factors: occurrence and diagnostic significance].

Sera from 80 patients suffering from rheumatoid arthritis--30 of them with extraarticular manifestations (EAM)--were analyzed for the presence of IgE rheumatoid factors (IgE RF), IgM RF, and immune complexes. Despite of a close correlation between IgM RF and IgE RF, IgE RF allow a better discrimination between patients with and without EAM (73.3 and 38.0%) compared to IgM RF (86.7 and 78.0%). IgE RF could be found in 5% of patients suffering from bronchial asthma, but up to now not in nonrheumatic joint diseases.

Antigen-Antibody Complex↗
PubMed1993

[In vitro IL-6- and immunoglobulin-production in patients with variable immunodeficiency syndrome (CVID)].

In vitro immunoglobulin and IL-6 synthesis were investigated in patients with CVID and healthy controls. The IL-6 production was increased in CVID patients. However, after calibration to equal monocyte counts in the mononuclear cell population the difference between patients and controls was no longer significant. The immunoglobulin production in CVID was decreased but no correlation between immunoglobulin and IL-6 production was found. From these results we suggest that monocyte activation might be of importance in terms of secondary organ lesions frequently occurring in CVID patients.

Cells, Cultured↗
PubMed1991

IgE rheumatoid factor. Occurrence and diagnostic importance in comparison with IgM rheumatoid factor and circulating immune complexes.

The sera of 80 patients suffering from rheumatoid arthritis (RA)--30 of them with extraarticular manifestations (EAM) and 50 patients with articular disease only--of 25 patients with other joint diseases and of 30 normal healthy subjects, were analyzed for the presence of 1) IgE rheumatoid factors (IgE RF) by means of a solid phase radioimmunoassay and an ELISA, 2) IgM rheumatoid factors by using solid phase radioimmune techniques, and 3) circulating immune complexes (CIC) with the C1q binding test (C1q BT) and the solid phase conglutinin binding test (SPCBT). The best technique to discriminate RA patients with EAM from RA patients without EAM and patients with other articular diseases was the determination of IgE RF (73.3%, 38.0%, 0%, resp.) compared to IgM RF (86.7%, 78.0%, and 56.0%) and CIC (C1q BT: 80.0%, 66.0% and 45.0%; SPCBT: 46.7%, 22.0%, and 20.0%). The results suggest a certain role of IgE RF for diagnosis and a possible development of extraarticular manifestations in rheumatoid arthritis.

Antigen-Antibody Complex↗
PubMed1991

Structure of respiratory allergens.

Respiratory allergens from one of the most important group of allergens. Except for professional allergens they are characterized by an enormous heterogeneity including a restricted number of major allergens. By means of modern immunological, chemical and genetic techniques some of them are, at least partially, characterized. Immunogenicity depends on a restricted area of the molecules. These epitopes seem to be in principle different for B cells (antibodies) and T cells. The strategies to improve immunodiagnosis are, therefore, not necessarily identical with those for the development of immunotherapy. The present data on selected respiratory allergens are summarized.

Allergens↗