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Biomedical subjects

U Schauer

Publications and source records attributed to U Schauer.

50 records · Page 3Linked to original sources
PubMed1991

Enhanced superoxide generation by eosinophils from asthmatic children.

In 21 asthmatic children, aged 2-19 years, and 11 age-matched controls purified (purity greater than 75%) peripheral blood eosinophils and neutrophils (purity greater than 95%) were stimulated with phorbol myristate acetate (44 ng/ml) for 30 min at 37 degrees C. The superoxide generation was determined as well as the superoxide dismutase inhibitable cytochrome c reduction. Eosinophils obtained from asthmatic patients displayed a significantly higher O2- generation (p less than 0.01) when compared to neutrophils from the same patients or to eosinophils and neutrophils from healthy controls. Preincubation with human recombinant granulocyte macrophage colony stimulating factor for 30 min or platelet-activating factor for 10 min resulted in augmented O2- generation by eosinophils from control, but not from asthmatic children, indicating a possible in vivo priming of eosinophils in asthma.

Adolescent↗
PubMed1990

Relationship between LTC4 generation of hypodense eosinophils and bronchial hyperreactivity in asthmatic children.

In 19 asthmatic children aged 6-16 years, the degree of bronchial hyperreactivity was determined in relationship to the concentration of inhaled histamine which caused a fall of the specific conductance (sGaw) to 60% of the baseline value PC60sGaw. At the time of lung function testing, a sample of heparinized blood was obtained from each patient. Eosinophils were purified and separated into a normodense and hypodense fraction by Percoll gradient centrifugation. After in vitro stimulation by ionophore A 23187, the leukotriene C4 (LTC4) content was determined in the culture supernatants. Hypodense eosinophils of the 13 children with a histamine threshold lower than 1 mg/ml generated significantly (p less than 0.01) larger amounts of LTC4 (0.8-36.3 ng/10(6) cells) when compared to 6 children with a histamine threshold higher than 1 mg/ml (0.7-12.1 ng/10(6) cells) and 12 healthy controls (0.4-8.2 ng/10(6) cells). Preincubation of eosinophils with platelet activating factor (PAF) induced an enhanced LTC4 production, not only in hypodense cells from both asthmatic groups but also in normodense cells from patients with severe hyperresponsiveness. These results are consistent with other results which suggest an important role of eosinophils, their activation by PAF and enhanced release of spasmogenic LTC4 in the pathogenesis of asthma.

Adolescent↗
PubMed1989

Detection of activated lymphocyte subsets by fluorescence and MTT staining.

A double staining technique for simultaneously determinating cell surface phenotype and the degree of cell activation is described. As an activation marker, the tetrazolium dye MTT has been used. Cells were incubated for 30 min with MTT. Activated cells yielded a granular staining pattern. Upon termination of the reaction with sodium azide, a double-step immunofluorescence staining procedure using monoclonal antibodies specific for cell surface antigens was performed. The percentage of cells simultaneously displaying MTT formation and fluorescence was microscopically evaluated. Our results demonstrate that MTT staining is expressed concomitantly with the IL-2 receptor and the transferrin receptor. This method permits a simple characterization of activated T cell subsets and can be used clinically to analyse the T cell functions of patients being treated with immunosuppressive agents and patients with acquired immune deficiency syndrome.

Acquired Immunodeficiency Syndrome↗
PubMed1989

Enhanced leukotriene C4 production by peripheral eosinophilic granulocytes from children with asthma.

Granulocytes and mononuclear cells were isolated from the blood of asthmatic and healthy children. Stimulation with ionophore A 23187 induced a significantly higher leukotriene C4 (LTC4) generation from granulocytes of asthmatic children than from granulocytes of healthy controls. In contrast, mononuclear cells from patients and controls did not differ in their ability to produce LTC4. Additional analysis showed that the difference in LTC4 generation of granulocytes was due to increased formation but not to decreased oxidative degradation of LTC4. Analysis of LTC4 generation of purified neutrophils and eosinophils revealed that LTC4 was generated almost exclusively by eosinophils and, in particular, the hypodense population. Granulocytes from patients with a history of severe asthma displayed a higher LTC4 formation than granulocytes from patients with less severe disease.

Adolescent↗
PubMed1989

Bronchial sensitization in guinea pigs following ingestion of ovalbumin.

Local bronchial mucosal hypersensitivity following antigen feeding was studied in the guinea pig. Groups of 6 animals were fed 1% ovalbumin (OA) in tap water or tap water without antigen (control group) for different feeding periods (14, 28, 42, and 56 days). Inhalative provocations with increasing concentrations of OA (0.5-8% OA) were performed at the end of each feeding period followed by body plethysmographic measurement of airway obstruction. Specific bronchial hypersensitivity to inhaled OA was not found in the control group, whereas specific bronchial reactivity to OA, described as reactivity index, was significantly different from the control group after 14 (p less than 0.05), 28 (p less than 0.001) and 42 days (p less than 0.01) of feeding. No difference to the control group was found after 56 days of feeding. Anti-OA IgG total and IgG1 in serum and bronchoalveolar lavage fluid were increased in OA-fed animals reaching maximal concentrations at day 28 of the feeding period. We conclude that oral feeding of a 1% solution of OA can induce a transient state of local hypersensitivity to inhaled antigen in the guinea pig as manifested by bronchoconstriction on OA inhalation and increased concentrations of local and systemic specific antibodies. This period of local hypersensitivity is followed by tolerance.

Aerosols↗
PubMed1988

B cell growth factor activity in supernatants of MRL-lpr/lpr derived T cell hybridomas.

The aim of this study was to characterize B cell growth factor (BCGF) activity derived from autoimmune MLR-lpr/lpr cells. In order to obtain supernatants containing BCGF that are free of suppressor lymphokines, MLR-lpr/lpr spleen cells were fused with BW 5147 thymoma cells to form T cell hybridomas. High fusion frequencies were obtained without prestimulation in vitro indicating a high degree of preactivation in vivo. Nineteen of 172 of the resulting hybridomas produced a B cell growth factor, which induced proliferation of small B cells when co-cultured with low doses of an anti-mu antibody. Maximal augmentation of B cell proliferation by supernatants containing BCGF required low cell concentrations and the presence of factor during the initiation of the culture. These data indicate that one of the possible active components of the supernatants containing BCGF is the recently characterized lymphokine interleukin 4 (IL-4).

Animals↗
PubMed1986

B lymphocyte activation by insoluble anti-mu antibodies in patients with systemic lupus erythematosus.

In order to study the capacity of anti-immunoglobulin (Ig) antibodies to induce proliferative responses in peripheral blood mononuclear cells (PBC) from patients with systemic lupus erythematosus (SLE), anti-mu coupled to Sepharose beads (anti-mu) was used as a polyclonal activator. In 18 patients, a strong proliferative response was associated with inactive disease, and the response was lower in clinical active disease (P less than 0.02). An inverse correlation could also be observed in six patients who were studied longitudinally (P less than 0.01). These results indicate that anti-mu responsiveness is closely related to disease activity in SLE. In addition, sequential data obtained from two patients during an early stage of clinical deterioration suggest that a low anti-mu response might be an early indicator of a clinical relapse. In the patients investigated, the anti-mu response was not correlated with the response to pokeweed mitogen (PWM), or with the quantity of B cells. When T cell depleted cell fractions were studied, marked increases in the proliferative responses to anti-mu were observed in some patients. These studies suggest that the response to anti-mu might be modified by T cells to a variable extent in patients with SLE.

Adult↗
PubMed1985

[Studies on B cell activation in collagenoses].

An inverse correlation between PWM and anti mu responses of peripheral blood lymphocytes, and a close relationship to clinical activity were demonstrated in 9 patients with systemic lupus erythematosus.

Arthritis, Rheumatoid↗
PubMed1984

Identification of immunoreactive forms of human erythrocyte band 3 in nonerythroid cells.

Antibodies directed to the cytoplasmic domain of human erythrocyte band 3, the major integral protein of the erythrocyte membrane which is thought to be the main anchoring site of the membrane cytoskeleton, were demonstrated in the present study to react with the membrane of various nonerythroid cells, such as human leucocytes, fibroblasts or human umbilical mesenchyme cells, amniotic epithelium and vascular smooth muscle. In cultured fibroblasts staining was confined to small dots and streaks associated with both the dorsal and ventral cell membrane. In human lymphocytes band 3 antigen accompanied capping of concanavalin A binding surface receptors. The immunoreactive form of band 3 in fibroblasts was shown by immunoblotting studies to be a polypeptide of approximately 60 000 dalton. This polypeptide is immunologically and electrophoretically related to a major immunoreactive form of band 3 naturally occurring in the red blood cell membrane. Considering the recent identification in nonerythroid cells of immunoreactive forms of other major components of the erythrocyte membrane cytoskeleton, the present observation in nucleated cells of a polypeptide related to erythrocyte band 3 may indicate some of the features of erythrocyte membrane architecture are also present in nonerythroid cells.

Animals↗
PubMed1980

The effect of propranolol treatment on total cholesterol, HDL cholesterol, triglycerides. Postheparin lipolytic activity and lecithin:cholesterol acyltransferase in hypertensive individuals.

Administration of 120 mg propranolol per day to hypertensive patients is followed by decreased plasma concentrations of total cholesterol and HDL cholesterol and increased concentrations of triglycerides. Postheparin lipolytic activity was reduced when measured 5 min after heparin administration. The activity of lecithin:cholesterol acyltransferase is diminished. Reduced activity of this enzyme by propranolol could be demonstrated in vitro as well.

Adolescent↗
PubMedDate not supplied

[Treatment of infants with RSV infection: a retrospective analysis of the season 1998/99].

Respiratory syncytial virus (RSV) is the most frequent cause of hospitalization for respiratory tract infection during the first 2 years of life. Recently the monoclonal antibody Palivizumab was approved for prophylaxis of RSV infection. Guidelines for the use of Palivizumab are based on data from North America and Great Britain. The epidemiology of RSV infection and patient management procedures may vary from one country to another. This study was designed to analyze the spectrum of patients hospitalized in Germany for RSV infection. During the 1998 to 1999 RSV season RSV-infected children admitted to twenty hospitals were followed. Of 222 RSV-infected patients 17.6 % (39) were born at 32 weeks of gestation or earlier and 16.2 % (36) between 33 weeks and 35 weeks. There were significant differences (P < 0.01) between the extremely preterm infants and the other patients in frequency of bronchopulmonary dysplasia, supplemental oxygen and age at hospital admission. In addition, both preterm groups had a significant longer length of hospital stay compared to the infants born at term. Thus, the current guidelines seem to be appropriate for selection of infants to receive RSV prophylaxis.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Fatal course of infectious mononucleosis in an 11-month-old girl].

Fatal infectious mononucleosis is vary rare in the human population. Only two case reports of girls suffering an Epstein-Barr virus-associated lymphoproliferation without evidence of an underlying immunodeficiency came to our knowledge. We report on the case of an 11-months-old girl with fatal infectious mononucleosis. Some findings allow distinct delineation from previous reports. Firstly, the present "pulmonary lymphoid hyperplasia" has been formerly described in patients with HIV infection exclusively. Secondly, only the EBV surface antigen LMP was expressed on infected B-cells. The nuclear antigen complex EBNA could not be demonstrated. Overall, the results suggest a so far unrecognised type of EBV-associated lymphoproliferation in a female infant.

B-Lymphocytes↗