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Biomedical subjects

D Maurer

Publications and source records attributed to D Maurer.

At least 73 records · Page 4Linked to original sources
PubMed1994

A review on Fc epsilon RI on human epidermal Langerhans cells.

In order to show the surface expression of Fc epsilon RI on human epidermal Langerhans cells (LC), we examined monomeric IgE binding to LC. We demonstrated that the majority of epidermal LC were able to bind monomeric IgE. IgE binding to LC could neither be prevented by preincubation of the tissue with monoclonal antibodies (mAb) against either Fc epsilon RII/CD23 or Fc gamma RII/CD32, nor by the addition of lactose, but could be entirely abrogated by preincubation with the anti-Fc epsilon RI mAb 15-1. These data show that epidermal LC express Fc epsilon RI molecules.

Humans↗
PubMed1993

[Immune mechanisms of atopic dermatitis].

The syndrome of atopy consists of three major clinical entities, i.e., allergic rhinoconjunctivitis, allergic asthma and atopic dermatitis, and is usually associated with elevated serum IgE levels. Whereas the pathogenetic role of IgE is clearly established in the case of allergic rhinoconjunctivitis and allergic asthma, the occurrence of atopic dermatitis cannot be easily explained by hyperimmunoglobulinemia E. Atopic dermatitis clinically presents as eczematization of certain predisposed (mostly flexural) areas of the skin. The clinical and histopathological picture, as well as the emergence kinetics of atopic eczema, roughly follow the criteria of delayed type (type IV) immune reactions. It is at present unclear whether the type I-like and the type IV-like allergic reactions of atopy are events occurring independently of each other or, alternatively, are pathogenetically linked to each other. Recent data suggest that in contrast to allergic contact dermatitis where Th 1-like T cells producing interleukin (IL)-2 and interferon (IFN)-gamma are the cells eliciting the lesions, the cellular infiltrate of atopic dermatitis lesions is dominated by Th2 cells capable of producing IL-4 and IL-5. Consequently, two clinical findings of atopic disorders are explicable by the observed Th2 cytokine secretion pattern i.e. i) the hypereosinophilia by the hyperproduction of IL-5 and ii) the hyperimmunoglobulinemia E, for which the presence of IL-4 is a "conditio sine qua non".(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1993

Sensitivity in the nasal and temporal hemifields in children treated for cataract.

PURPOSE: To determine if form-deprived aphakes, like normal infants, show especially poor sensitivity in the nasal visual field. The purpose of this article was also to examine the influence on their peripheral sensitivity of the timing and duration of deprivation, of whether deprivation was monocular or binocular, and of having patched the fellow nondeprived eye. METHODS: Static perimetry was used to measure intensity thresholds at 20 degrees in the nasal visual field and at 30 degrees in the temporal visual field in normal subjects (n = 20 7-year-old children, 20 8-year-old children, 12 9-year-old children, and 20 adults) and in 46 children treated for a dense and central cataract in one (n = 21) or both (n = 25) eyes. The deprivation began either at birth or after a normal early history, and the duration of deprivation varied widely among patients. Also tested were two adults who had been treated promptly for unilateral cataracts that had developed after the age of 40 years. RESULTS: In normal subjects, sensitivity was slightly higher at 20 degrees nasally than at 30 degrees temporally, with no developmental changes in sensitivity at either location. The deprived eyes of the children had losses in sensitivity at both locations but only children treated for unilateral congenital cataract had larger losses at 20 degrees nasally than at 30 degrees temporally. There were no significant effects on their sensitivity of the duration of deprivation or, in children treated for unilateral cataract, of patching of the nondeprived eye. In contrast, the two patients in whom cataracts did not develop until adulthood had normal sensitivity. CONCLUSIONS: Pattern deprivation interferes with the development of peripheral sensitivity at both 30 degrees temporally and 20 degrees nasally. Nasal sensitivity, which is slow to mature, is affected more by early monocular deprivation than by early binocular deprivation. The results are consistent with the hypothesis that unfair interocular competition during early infancy especially affects visual functions that are slow to mature.

Adolescent↗
PubMed1993

Stereopsis after congenital cataract.

PURPOSE: The authors determined whether stereopsis can be demonstrated in children treated for congenital cataract after compensating for their amblyopia and strabismus. METHODS: A custom-made set of large stereograms was used to compensate for amblyopia and presented in a synoptophore to facilitate motor fusion. Each pair of stereograms contained five wide vertical bars of high contrast, of which two or three were in crossed disparity. The authors aligned the stimuli in the synoptophore, then decreased the disparity until the child could no longer identify which bars appeared to be "in front." RESULTS: In normal children (n = 25), stereo acuity on this test (Tytla-Lewis-Maurer-Brent [TLMB] test) correlated well with the Titmus and Randot results within the ranges measured by those tests. Seven children in whom a traumatic cataract had developed after 6 yr of age (four with no clinical stereopsis) had TLMB test stereo acuities ranging from 225 to 28 arc-sec. Of 30 children treated for congenital cataract with no clinical stereopsis, 5 regularly achieved a TLMB stereo acuity of up to 225 arc-sec, and 2 with Titmus stereo acuities up to 200 arc-sec, each had a TLMB stereo acuity of 112 arc-sec. These seven congenital cases (two unilateral and five bilateral) with measurable TLMB acuities are among those with the shortest deprivation, the highest minimum resolvable acuity, and the highest contrast sensitivity. CONCLUSIONS: By compensating for amblyopia and strabismus, stereopsis can be demonstrated in some form-deprived amblyopic patients.

Adolescent↗
PubMed1992

IgM and IgG but not cytokine secretion is restricted to the CD27+ B lymphocyte subset.

In a recent study we reported that CD27 is expressed on a subpopulation of human B lymphocytes and presented circumstantial phenotypic evidence that CD27 expression may be acquired late during B cell differentiation. Here we present functional data showing that, after in vitro stimulation, CD27+ but not CD27- B cells secrete large amounts of both IgM and IgG. Using double immunofluorescence staining of CD27 and IgD, three functionally different B cell subsets representing distinct stages of B cell differentiation can be isolated: 1) the CD27- IgD+ B cells, which do not secrete appreciable Ig; 2) the CD27+IgD+ B cells, which exclusively secrete IgM; and 3) the CD27+IgD- B cells, which comprise the IgG-producing cells. Furthermore, costimulation of CD27- B cells with low m.w. B cell growth factor, in the presence or in the absence of a CD40 mAb, does not induce these cells to become Ig-secreting cells. Although CD27- B cells hardly secrete Ig of any isotype in response to Staphylococcus aureus+IL-2, these cells proliferate vigorously and express the IL-2R alpha chain (CD25) under these stimulatory conditions. Furthermore, both CD27- and CD27+ B cells are capable of producing similar amounts of IL-6 and TNF-alpha. Taken together, these findings indicate that CD27 is a unique non-Ig surface marker discriminating naive from primed B lymphocytes. Furthermore, the capacity to proliferate and to secrete the B cell differentiation factors IL-6 and TNF-alpha already exists at an early B cell differentiation stage at which the cells lack CD27 expression and are not induced to produce Ig.

Antigens, CD↗
PubMed1992

Epidermal Langerhans cells from normal human skin bind monomeric IgE via Fc epsilon RI.

Human epidermal Langerhans cells (LC) bearing IgE are found in disease states associated with hyperimmunoglobulinemia E. When studying the mechanism(s) underlying this phenomenon, immunohistology revealed that a majority of epidermal LC from normal skin of healthy individuals can specifically bind monomeric IgE. IgE binding to LC could neither be prevented by preincubation of the tissue with monoclonal antibodies (mAb) against either Fc epsilon RII/CD23 or Fc gamma RII/CD32, nor by the addition of lactose. However, binding could be entirely abrogated by preincubation with the anti-Fc epsilon RI alpha mAb 15-1, which interferes with IgE binding to Fc epsilon RI alpha gamma transfectants. These observations indicated that IgE binding to epidermal LC is mediated by Fc epsilon RI rather than by CD23, CD32, or the D-galactose-specific IgE-binding protein. This assumption gained support from our additional findings that: (a) the majority of LC exhibited distinct surface immunolabeling with the anti-Fc epsilon RI alpha mAbs 15-1 and 19-1, but not with any of eight different anti-Fc epsilon RII/CD23 mAbs; and (b) transcripts for the alpha, beta, and gamma chains of Fc epsilon RI could be amplified by polymerase chain reaction from RNA preparations of LC-enriched, but not of LC-depleted, epidermal cell suspensions. In view of the preeminent role of Fc epsilon RI crosslinking on mast cells and basophils in triggering the synthesis and release of mediators of allergic reactions, the demonstration of this receptor on epidermal LC may have important implications for our understanding of allergic reactions after epicutaneous contact with allergens.

Animals↗
PubMed1992

Phenotypic analysis of functionally associated molecules on peripheral blood and synovial fluid monocytes from arthritis patients.

Surface expression of 16 different membrane molecules was analyzed in peripheral blood and synovial fluid monocytes from patients with rheumatoid arthritis and reactive arthritis compared to controls. The most significant findings were modulated expression of function-associated FcRI, CR1, CR3, MHC class II and activation-associated CD31, M5, and M6 molecules in arthritis patients compared to controls. Of these molecules, only upregulated expression of MHC class II has previously been reported in synovial fluid monocytes of patients with rheumatoid arthritis.

Antibodies, Monoclonal↗
PubMed1992

The development of the temporal and nasal visual fields during infancy.

We used static perimetry to measure the development of the monocular visual field during infancy. Infants from birth to 6 months of age, and adults, were shown a 3 or 6 degrees flashing light at various locations between 15 and 120 degrees in the temporal and nasal visual fields. We assumed that subjects could see a light if they moved their eyes toward it more often than they looked in the same direction on blank control trials. For both the 3 and 6 degrees lights, the visual field expanded with age from the center out, and development in the nasal visual field lagged behind development in the temporal visual field. Possible reasons for these findings are discussed.

Adult↗
PubMed1992

Vision in the "good" eye of children treated for unilateral congenital cataract.

PURPOSE: The authors examined linear acuity and contrast sensitivity in the "good" (fellow) eye of children treated for unilateral congenital cataract to determine (1) whether there were subtle deficits like those described for the good eye of patients with strabismic amblyopia and (2) whether any deficits were related to the degree to which the good eye had been patched. METHODS: The authors tested patients treated for unilateral congenital cataract who had a well-documented history of patching. The good eye was physically normal with minimal refractive error. The measures were linear acuity at far (n = 15) and contrast sensitivity (n = 9). RESULTS: Compared with age-matched control subjects, the good eyes of patients had subtle deficits in linear acuity and in contrast sensitivity at high spatial frequencies. These deficits occurred even in eyes that had received minimal patching, and their severity was not related systematically to the duration of patching, which varied widely across the group. CONCLUSION: The visual sensitivity of the good eye of children treated for unilateral congenital cataract is, on average, slightly reduced, even in cases of minimal patching. Consequently, any deficits discovered after aggressive patching may not have been caused by occlusion amblyopia.

Adolescent↗
PubMed1992

Evidence for the presence of activated CD4 T cells with naive phenotype in the peripheral blood of patients with rheumatoid arthritis.

We have investigated whether T cell activation in rheumatoid arthritis (RA) preferentially engages distinct T cell subpopulations in the peripheral blood (PB) and in the synovial fluid. We found that CD25 expression was enhanced among PB CD4 T cells of RA patients as compared with CD4 cells of patients with reactive arthritis, degenerative joint disease or of healthy controls. Within the CD4 T lymphocytes subset we found that the CD45RO- (naive) cells selectively in RA displayed higher levels of CD25 protein and of interferon-gamma mRNA expression when compared with the respective subset of all other investigated groups. These results show that in the PB of RA, but not in the PB of the other arthropathies or healthy controls, CD45RO-CD4 T lymphocytes exist which display well-defined signs of activation.

Aged↗
PubMed1992

Phenotype of human T cells expressing CD31, a molecule of the immunoglobulin supergene family.

The CD31 molecule is a leucocyte-surface glycoprotein of 130 kDa with homology to the immunoglobulin gene superfamily. In this study we report on the expression of CD31 on human T cells and demonstrate that it subdivides peripheral blood T lymphocytes into two novel subsets. CD31 is expressed by 38% of CD3+ lymphocytes. About 85% of CD31+ T cells display the CD45RA phenotype, 35% the CD45RO phenotype, 24% the CD4 phenotype and 72% the CD8 phenotype. There is also a correlation between CD31 expression and CD45RA expression in cord blood T cells; 89% of CD3+ cord blood cells express CD31, and most of them have the CD45RA phenotype. A discrepancy was found with thymocytes, which are positive for CD31 but negative for CD45RA. Stimulation of human T cells leads to down-regulation of CD45RA, while CD31 continues to be expressed. In functional studies, CD31 antibody binding to T lymphocytes does not lead to mobilization of intracellular calcium, proliferation or modulation of T-cell proliferation.

Antibodies, Monoclonal↗
PubMed1991

IL-4 regulates c-kit proto-oncogene product expression in human mast and myeloid progenitor cells.

The c-kit proto-oncogene encodes the receptor for a novel hemopoietic cytokine, termed stem cell factor (SCF) or mast cell growth factor (MGF) according to its stimulating spectrum. The human receptor for SCF/MGF is expressed in a subset of normal bone marrow progenitor cells, in leukemic myeloid cells, and in mast cells. In the present study, the effects of recombinant human growth regulators (IL-1 through -9, granulocyte-macrophage/granulocyte/macrophage-CSF, IFN, and TNF) on c-kit proto-oncogene product expression were analyzed by indirect immunofluorescence, by using the anti-SCF/MGFR mAb YB5.B8, and Northern blot analyses, by using a c-kit oligonucleotide probe. Of all cytokines tested, IL-4 was found to down-regulate expression of YB5.B8 Ag in the human mast cell line HMC-1 (maximum inhibition, 51.05 +/- 16.36% mean fluorescence intensity of control; p less than 0.02), as well as in primary leukemic myeloid cells. IL-4 was also found to down-regulate expression of YB5.B8 Ag in normal enriched bone marrow progenitor cells. The effects of IL-4 on expression of YB8.B8 Ag in myeloid/mast cell progenitors was dose and time dependent (maximum effects observed on days 2 and/or 4, by using 50 U/ml of rIL-4) and could be neutralized by using anti-IL-4 mAb. Moreover, IL-4 was found to down-regulate expression of c-kit mRNA in leukemic myeloid cells as well as in HMC-1 cells. Together, these observations identify IL-4 as a regulator of c-kit proto-oncogene product expression in the human system. The effects of IL-4 on human hemopoietic progenitor cells and mast cells may be mediated in part through regulation of SCF/MGFR expression.

Antibodies, Monoclonal↗
PubMed1991

Interleukin 4 promotes expression of mast cell ICAM-1 antigen.

Cell recognition molecules play a crucial role in the regulation of immune cells. We recently found that mast cells (MCs) express leukocyte recognition molecules, including ICAM-1 antigen, a natural ligand of LFA-1. We here report that interleukin 4 (IL-4), a pleiotropic cytokine and mast cell differentiation factor, selectively promotes expression of surface ICAM-1 antigen and ICAM-1 mRNA in human MCs. IL-4 also up-regulates ICAM-1 antigen in cells of monocyte/macrophage lineage but has no effect on ICAM-1 antigen expressed on basophils, fibroblasts, or lymphocytes. The increase in expression of mast cell/macrophage ICAM-1 antigen induced by IL-4 may contribute to the accumulation of leukocytes and facilitate cell-contact-dependent regulation of immune cells in inflamed tissues.

Antigens, CD↗
PubMed1991

Transfer of polymorphic monoclonal antibody epitopes to the first and second domains of HLA-DR beta-chains by site-directed mutagenesis.

We used site-directed mutagenesis of HLA-DR beta-chains to localize the binding sites for two polymorphic DR-binding mAb to residues in the first and second external domains, respectively. Transfer of three first domain alpha-helical residues, G73, R74 and N77, normally present in DR3a and DRw52a, to a DR4 beta-chain was sufficient for recognition of this mutant DR molecule by a DR3-specific mAb, NDS 9. A polymorphism controlling the binding of a DR4-specific mAb, GS 359-13F10, was mapped to a tyrosine at position 96 of the DR4 beta-chain second domain by the construction fo a chimeric DR molecule containing a DR2-first domain and DR4-second domain. The mapping of these two polymorphic epitopes to specific positions on the DR beta-chain will allow further structural and functional analysis of the DR molecule.

Amino Acid Sequence↗
PubMed1991

Analysis of function-associated receptor molecules on peripheral blood and synovial fluid granulocytes from patients with rheumatoid and reactive arthritis.

In this study we report the expression pattern of 13 different function-associated surface molecules on synovial fluid and peripheral blood granulocytes from rheumatoid and reactive arthritis patients. We found increased expression of the complement receptors 1 (CD35) and 3 (CD11b) and of the activation-associated antigens CD67, CD24, and M5 on synovial fluid granulocytes from rheumatoid and/or reactive arthritis patients compared to autologous peripheral blood granulocytes. In addition, synovial fluid granulocytes expressed IgG Fc receptor 1 (CD64) and complement receptor 4 (CD11c), neither of which can be found on peripheral blood granulocytes. Peripheral blood granulocytes from rheumatoid and reactive arthritis patients expressed higher levels of leucocyte function-associated antigen 1 (CD11a) and of the membrane proteins CD31, CD24, M5, and M6 compared to peripheral blood granulocytes from healthy controls and patients with degenerative joint disease. No significant differences in the expression of any of the molecules studied could be observed between cells from rheumatoid and cells from reactive arthritis patients, suggesting a similar activation process for granulocytes in these two diseases.

Antigens, CD↗
PubMed1991

Ratio of complement receptor over Fc-receptor III expression: a sensitive parameter to monitor granulocyte-macrophage colony-stimulating factor effects on neutrophils.

In vitro activation of human granulocytes leads to altered expression of distinct surface antigens. Compared with the changes observed with classic activating reagents such as the phorbol ester PMA similar, but less pronounced alterations of surface antigen expression were observed upon granulocyte activation with human recombinant granulocyte-macrophage colony-stimulating factor (hrGM-CSF). In particular, stimulation with hrGM-CSF is followed by an enhanced expression of the complement receptors CD35 (CR1) and CD11b (CR3) while the low affinity Fc-gamma receptor CD16 (FcRIII) is downregulated. In order to investigate whether there are similar effects under in vivo conditions, we studied the granulocytes from patients undergoing rhGM-CSF therapy before, during, and after treatment. We found a marked increase in CD35 (CR1) and CD11b (CR3) expression and a substantial decrease or even loss of CD16 (FcRIII) on these granulocytes. These changes correlated well with our in vitro data and occurred extremely rapidly after therapy onset. Furthermore, therapy monitoring using ratios calculated by the mean fluorescence channel numbers of CR and FcRIII stainings may combine the advantage of high sensitivity with high reproducibility as a result of the contrasting change in CR and FcRIII expression during granulocyte activation. Being nonparametric values, such ratios are not influenced by individual flow cytometry standardization. Taken together, these activation-associated changes of surface receptor expression and especially of CR over FcRIII ratios are useful parameters for monitoring the in vivo effects of rhGM-CSF.

Antigens, CD↗
PubMed1991

Formant movement and formant number alteration with rising FO in real vocalizations of the German vowels [u:], [o:] and [a:].

Production theory explains vowel sounds by formants in terms of a resonance pattern of the vocal tract. In perception theory normalization must also be undertaken because of different formant values for one vowel category, as found in comparisons of men, women and children, and in studies of sung vowels and of synthesized vowel sounds. Synthesis indicates a dependence of the formants on FO. Therefore, the question arises whether the formant pattern is directly related to FO when studied in real vocalizations. This study presents: a. a method to determine formant movement in real vocalizations for all FO, and b. the results of spectral and LPC analysis of the three German vowels [u:], [o:] and [a:] in real vocalizations. The need for formant movement with altering FO, as well as a change in the number of formants with altering FO, is demonstrated. The implications of these results for normalization in the description of the physics of the vowel sound wave are discussed.

Adolescent↗