Sumatriptan causes parallel decrease in plasma CGRP concentration and migraine headache during nitroglycerin-induced migraine attack.
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Biomarkers↗
Biomedical subjects
B Van der Schueren
Publications and source records attributed to B Van der Schueren.
Cough as the presenting symptom of large vessel vasculitis.
We report the case of a 57-year-old woman presenting with persistent cough, weight loss, and fever. An extensive work-up revealed laboratory signs of inflammation and a mild thickening of the aortic wall on computed tomographic scan of the thorax. These findings raised the suspicion of large vessel vasculitis that was elegantly confirmed by fluorodeoxyglucose positron emission tomography. Persistent cough as the inaugural symptom and involvement of large vessels in Horton's disease are also discussed.
Aorta, Abdominal↗
Ciliary function analysis for the diagnosis of primary ciliary dyskinesia: advantages of ciliogenesis in culture.
The gold standard for the diagnosis of primary ciliary dyskinesia (PCD) is a dynein deficiency shown with transmission electron microscopy. However, there are many cases of PCD without dynein deficiency. When considering ciliary function, there are similar problems of sensitivity in diagnosis and there is also a major lack of specificity. Based on the normal ciliary function and ultrastructure and the absence of secondary abnormalities after ciliogenesis in sequential monolayer-suspension culture, the diagnostic value of ciliary function analysis after ciliogenesis was investigated in more than 70 PCD and 640 non-PCD cases. In biopsies, ciliary immotility was found in 66% of PCD cases but was also found in 8% of non-PCD cases. PCD was later confirmed in 61% of the biopsies with ciliary immotility. Normal ciliary beat frequency (CBF) was found in 20% of PCD biopsies. Coordinated ciliary activity was observed in 10% of PCD cases. After ciliogenesis in culture, ciliary immotility was present in 78% of the PCD cases but never in non-PCD cases. CBF was normal after ciliogenesis in 7% of the PCD cases and was always found in non-PCD cases. Absence of coordinated ciliary activity was found in 100% of PCD cases and 0% of non-PCD cases. In conclusion, while ciliary function analysis in a biopsy never proves, nor excludes the diagnosis of PCD, after ciliogenesis in culture CBF measurement can be diagnostic for PCD and reaches 100% specificity and sensitivity when considering coordinated ciliary activity, making it the single 100% diagnostic parameter for PCD.
Biopsy↗
Dynein arms and spokes after ciliogenesis in cultured respiratory epithelial cells from non-PCD individuals.
Dynein arms and spokes are crucial components of cilia. Reference values for the dynein arms and spokes were calculated based on biopsies from non-PCD patients as well as after ciliogenesis in culture. The mean values in the biopsies (n = 251) were 8.4 +/- 0.5, 2.9 +/- 0.7 and 4.7 +/- 1.0 for the outer dynein arms, inner dynein arms and spokes respectively. After ciliogenesis in culture (n = 462) identical values were found: 8.7 +/- 0.4, 3.0 +/- 0.4 and 5.5 +/- 0.6. The lower limits of normality can be set at 7.0 and 1.2 for the outer and inner dynein arms respectively. The dynein arms and spokes were not influenced by the percentage of secondary abnormalities. In conclusion, dynein arms and spokes are readily identified after ciliogenesis in culture. These parameters are independent of secondary ciliary dyskinesia.
Biopsy↗
Secondary ciliary dyskinesia is absent after ciliogenesis in culture.
Ultrastructural secondary ciliary dyskinesia (SCD) was measured using transmission electron microscopy in 301 biopsies and 439 samples after ciliogenesis in the sequential monolayer-suspension culture. Biopsies were taken in the context of exclusion of primary ciliary dyskinesia. SCD was frequently found in the biopsies: only 30% of the samples were normal (SCD < 5%), the mean percentage of SCD abnormalities was 11.9 +/- 12.9%. In 1/8 of the samples severe SCD (> 25%) was present. The most frequently encountered SCD abnormality was the membrane bleb, followed by the various peripheral microtubular abnormalities. With increasing total SCD the absence of the central pair became more important. After ciliogenesis in culture SCD was virtually absent: 1.0 +/- 1.8% for all 439 samples, 96% of the samples were within limits of normality (SCD < 5%). Moderate (15-25%) and severe SCD (> 25%) were never found. In more than 50% of the samples not one abnormality was found. There was no relation between the SCD in the biopsy and that after ciliogenesis. The absence of SCD after ciliogenesis is a major advantage for the diagnosis of PCD, specifically in cases with central pair abnormalities, peripheral microtubular pair abnormalities and those without a primary ultrastructural abnormality.
Biopsy↗
Ultrastructural expression of primary ciliary dyskinesia after ciliogenesis in culture.
During the period 1990-1999 84 PCD patients were identified and characterized. The expression of inherited abnormalities in primary ciliary dyskinesia after ciliogenesis was investigated in 41 patients with dynein deficiency, 6 patients with absence of the central pair of microtubules and 24 PCD patients with normal ultrastructure. In patients with dynein deficiency, the outer dynein arms counts were 1.9 +/- 1.0 in the biopsies and 1.6 +/- 0.7 after ciliogenesis. Secondary abnormalities were found in 15.8 +/- 20.4% of the transverse sections of cilia and only in 1.0 +/- 1.3% after ciliogenesis. Ciliary orientation was 28 +/- 11 degrees and 24 +/- 10 degrees respectively in biopsies and cultures. In patients with absence of the central pair this was found in 15 +/- 16% in biopsies and 21 +/- 19% after ciliogenesis. The values for the outer dynein arm were 8.4 +/- 0.3 and 8.7 +/- 0.2 and for the secondary abnormalities were 11.7 +/- 7.3% and 0.5 +/- 1.3% in the biopsies, respectively after ciliogenesis. In patients with normal ultrastructure the scores for the dynein arms were similar. Secondary abnormalities were found in 12.2 +/- 11.7% in the biopsies and 0.6 +/- 0.9% after ciliogenesis while ciliary orientation was respectively 21 +/- 7 degrees and 25 +/- 8 degrees. In conclusion, inherited abnormalities in primary ciliary dyskinesia are expressed after ciliogenesis, while secondary abnormalities are virtually absent, thereby facilitating the ultrastructural diagnosis.
Biopsy↗
Nasal ciliary beat frequency is age independent.
OBJECTIVES: Evaluate the age-dependency of ciliary beat frequency (CBF) in biopsies after ciliogenesis in culture. STUDY DESIGN: Retrospective analysis of CBF and ciliary ultrastructure in biopsies and after ciliogenesis from 203 individuals, aged 3 months to 74 years. METHODS: All patients with successful culture were included. Ciliogenesis was obtained using the sequential monolayer-suspension culture technique for dissociated nasal epithelial cells. CBF was measured using computerized microscope photometry. Secondary ultrastructural abnormalities were evaluated in transmission electron microscopy. RESULTS: There was no correlation between age and CBF, in either the biopsies (7.0 +/- 2.6 Hz; n = 113) or after ciliogenesis in culture (8.1 +/- 1.3 Hz; n = 203). Even in individuals older than 70 years, CBF was normal in bioptic material (6.7 +/- 1.7 Hz) and after ciliogenesis in culture (7.9 +/- 1.0 Hz). Also, in individuals less than 1 year of age CBF was normal in biopsies as well as after ciliogenesis. CBF correlated inversely with the percentage of secondary ultrastructural abnormalities in the biopsies as seen with transmission electron microscopy: 8.1 +/- 1.8 Hz when ciliary ultrastructure was normal and 3.5 +/- 3.3 Hz in cases of severe secondary ciliary dyskinesia. After ciliogenesis in culture, ciliary ultrastructure was always normal, as was CBF. CONCLUSION: CBF is age independent but correlates with secondary ultrastructural abnormalities. CBF after ciliogenesis in culture is the intrinsic one.
Adolescent↗
Heparan sulfate expression in polarized epithelial cells: the apical sorting of glypican (GPI-anchored proteoglycan) is inversely related to its heparan sulfate content.
Several processes that occur in the luminal compartments of the tissues are modulated by heparin-like polysaccharides. To identify proteins responsible for the expression of heparan sulfate at the apex of polarized cells, we investigated the polarity of the expression of the cell surface heparan sulfate proteoglycans in CaCo-2 cells. Domain-specific biotinylation of the apical and basolateral membranes of these cells identified glypican, a GPI-linked heparan sulfate proteoglycan, as the major source of apical heparan sulfate. Yet, most of this proteoglycan was expressed at the basolateral surface, an unexpected finding for a glypiated protein. Metabolic labeling and chase experiments indicated that sorting mechanisms, rather than differential turnover, accounted for this bipolar expression of glypican. Chlorate treatment did not affect the polarity of the expression of glypican in CaCo-2 cells, and transfectant MDCK cells expressed wild-type glypican and a syndecan-4/glypican chimera also in an essentially unpolarized fashion. Yet, complete removal of the heparan sulfate glycanation sites from the glypican core protein resulted in the nearly exclusive apical targeting of glypican in the transfectants, whereas two- and one-chain mutant forms had intermediate distributions. These results indicate that glypican accounts for the expression of apical heparan sulfate, but that glycanation of the core protein antagonizes the activity of the apical sorting signal conveyed by the GPI anchor of this proteoglycan. A possible implication of these findings is that heparan sulfate glycanation may be a determinant of the subcellular expression of glypican. Alternatively, inverse glycanation-apical sorting relationships in glypican may insure near constant deliveries of HS to the apical compartment, or "active" GPI-mediated entry of heparan sulfate into apical membrane compartments may require the overriding of this antagonizing effect of the heparan sulfate chains.
Animals↗
A 68-kD antigen, which is probably an N-terminal fragment of the VLA-5 alpha 5-subunit, is specific for differentiating keratinocytes.
BACKGROUND: During terminal differentiation, basal keratinocytes lose gradually contact with the basement membrane, a process accompanied by the progressive functional down-regulation and loss of integrin expression. Understanding the molecular nature of this complex mechanism will eventually lead to insight into the pathogenesis of differentiation disorders of the epidermis, e.g. psoriasis. OBJECTIVE: The monoclonal antibody 8D9 against the very late antigen 5 (VLA-5) integrin subunit was used to study the expression and down-regulation of this protein in several experimental paradigms of keratinocyte differentiation. METHODS: Primary cultures of human keratinocytes were prepared and used as such, or after induction of terminal differentiation with methylcellulose and/or calcium. Expression of the 8D9 epitope was analyzed using immunoblotting, protein chemistry and immunocytochemistry on cultured cells and on skin biopsies from control and psoriatic patients. RESULTS AND CONCLUSION: The monoclonal antibody 8D9 reacts with the alpha 5-subunit of human VLA-5 integrin and with a 68-kD antigen that is strongly expressed in differentiating keratinocytes in vitro and in the cornified layers of human skin in vivo. Psoriatic skin showed additional immunoreactivity in the upper spinous and granular layers. Based on indirect immunological and chemical evidence we suggest that the 68-kD protein is an amino-terminal degradation product of the alpha 5-subunit, which provides a new and interesting marker of differentiating keratinocytes.
Antibodies, Monoclonal↗
Localization of alpha 4m integrin at sites of mesenchyme condensation during embryonic mouse development.
The expression and distribution of the murine alpha 4 (alpha 4m) integrin subunit and of one of its ligands, VCAM-1, were examined in the developing mouse embryo at different development stages. Transcription of the mRNA was investigated by in situ hybridization using single-stranded sense and anti-sense cDNA probes and by Northern blotting. In parallel sections integrin was identified by immunohistochemistry using the alpha 4m-specific antibody R1/2. In general both methods gave similar distributions. The results demonstrate that alpha 4m and vascular cell adhesion molecule-1 (VCAM-1) are expressed in mouse embryonic liver (E11-E15) and are developmentally down-regulated, consistent with the haematopoietic properties of embryonic liver. Developmental-stage-dependent expression of alpha 4m was also observed in lymphoid organs, such as spleen and thymus, and in some non-lymphoid organs or tissues, such as skeletal and tongue muscles, smooth muscles of the blood vessels, the outflow tract of the embryonic heart, the papilla of the tooth, the glomeruli of the kidney and the stroma of the gonads. In the latter tissues, the expression of alpha 4m correlated with the transient condensation of particular mesenchymal structures. We also confirm that VCAM-1 and alpha 4 beta 1 are co-distributed only in some tissues, suggesting that during mouse development, VLA-4 interacts mainly with another ligand, probably fibronectin.
Animals↗
Differential expression of multiple cell-surface heparan sulfate proteoglycans during embryonic tooth development.
Heparan sulfate accumulates on cell surfaces and at cell-matrix interfaces, and functionally modulates several of the effector molecules that support the interactions, growth, and differentiation of developing tissues. Using heparin sulfate-specific monoclonal antibodies MAb, we obtained evidence that extracts from rodent embryos contain multiple forms of cell surface-associated heparan sulfate proteoglycan (PG). Taking tooth development in the mouse embryo as a model to further investigate the relevance of this PG redundancy and using MAb against heparan sulfate, antibodies specific for syndecan (syndecan-1) and fibroglycan (syndecan-2) (two distinct members of a larger family of cell-surface heparan sulfate PGs), and specific cDNA probes for these two cell-surface PGs, we obtained in situ evidence for regulated and differential expression of multiple cell-surface heparan sulfate PGs. The unique, distinctive, and coordinated changes in the expressions of these PGs during morphogenesis and differentiation of dental tissues suggest that the various cell-surface PGs are not truly redundant but play important, specific, and potentially complementary roles during embryonic development.
Animals↗
Spatial and temporal changes in the expression of fibroglycan (syndecan-2) during mouse embryonic development.
Fibroglycan (syndecan-2) is a member of a family of cell surface heparan sulfate proteoglycans that interact with adhesion molecules, growth factors and a variety of other effector systems that support the shaping, maintenance and repair of an organism. To investigate this apparent redundancy of proteoglycans at the cell surface, we have studied the expression of fibroglycan in the mouse embryo and compared this expression with that of syndecan-1. The characterisation of mouse embryo cDNA clones that crosshybridized to human fibroglycan-cDNA predicted that murine and human fibroglycan were highly similar in structure. Consistently, the analysis of transfectant cells, murine cell lines and embryo extracts indicated that the murine proteoglycan reacted specifically with monoclonal antibody 10H4 developed against the human protein. Fibroglycan, as detected by monoclonal antibody 10H4 in sections of embryonic tissues, occurred exclusively on mesenchymal cells that represented the putative precursors of the hard and connective tissue cells. No fibroglycan was detected in epithelia or in muscle cells. Areas where fibroglycan was particularly abundant were sites of high morphogenetic activity where intense cell-cell and cell-matrix interactions are known to occur (e.g. the epithelial-mesenchymal interfaces, the prechondrogenic and preosteogenic mesenchymal condensations). The expression of fibroglycan was weak in the early embryo, culminated during the morphogenetic phase and at the moment of cell lineage differentiation, and persisted in the perichondrium, periosteum and connective tissue cells. Syndecan-1, in contrast, was primarily detected in epithelia, and transiently in some mesenchymal cells, with mesenchymal localisations that did not or only partially overlap with those of fibroglycan. In situ hybridization analyses confirmed these expression patterns at the transcriptional level, identifying mesenchymal cells as the major source of fibroglycan production. These data indicate that the expression of fibroglycan occurs along unique and developmentally regulated patterns, and suggest that fibroglycan and syndecan-1 may have distinctive functions during tissue morphogenesis and differentiation.
Amino Acid Sequence↗
Aplasia of respiratory tract cilia.
We report on ciliary aplasia of the respiratory tract, a rare disorder of the mucociliary apparatus, that is insufficiently recognized as a distinct entity. A culture method for ciliogenesis was developed by our laboratory and offers the advantage of studying cilia free of secondary changes associated with infection. Three cases of primary ciliary aplasia were documented histologically in direct biopsy specimens and also in biopsy specimens cultured specifically for ciliogenesis. Primary ciliary aplasia should be differentiated from secondary ciliary aplasia in which basal bodies are present and ciliogenesis takes place in specific culture. Only hereditary ciliary abnormalities are expressed in cell cultures. We critically review the cases of ciliary aplasia reported to date.
Bronchi↗
Developmental changes in heparan sulfate expression: in situ detection with mAbs.
Two mAbs that are specific for heparan sulfate-related epitopes have been raised and used to analyze the cellular and tissular distribution of this glycosaminoglycan during development. mAb 10E4 reacts with an epitope that occurs in native heparan sulfate chains and that is destroyed by N-desulfation of the glycosaminoglycan. The antibody does not react with hyaluronate, chondroitin sulfate, or DNA, and reacts only poorly with heparin. The reactivity of proteoglycan extracts or tissue sections with the 10E4 antibody is completely abolished by heparitinase, but is only partially affected by heparinase. mAb 3G10, in contrast, reacts only with heparitinase-treated heparan sulfate chains, proteoglycans, or tissue sections. The 3G10 epitope is destroyed by treatment with mercuric acetate, which indicates that the desaturated uronate generated by the lyase is essential for the reactivity of the antibody. The 3G10 epitope is not generated by treating heparan sulfate proteoglycans with heparinase or chondroitin sulfate proteoglycans with chondroitin sulfate lyases, which indicates that the 3G10 antibody recognizes desaturated uronates that occur in specific structural contexts. The antibody 10E4 and, after heparitinase treatment, the antibody 3G10 decorate the surfaces of many cell types and the extracellular matrix in proximity of the cells, in particular, the basement membranes. The analysis of embryonic and adult tissues reveals important temporal and regional differences in the abundance of the 10E4 and 3G10 epitopes at these sites. Moreover, the staining pattern of the two antibodies is not always superimposable, which is indicative of regional differences in the exposure or structure of the tissular heparan sulfates. As a whole the results suggest that heparan sulfate abounds at sites of active morphogenesis and that the expression of this glycosaminoglycan is developmentally regulated.
Animals↗
In vitro ciliogenesis in respiratory epithelium of cystic fibrosis patients.
Nasal epithelial cells, dissociated from nasal polyps of three cystic fibrosis patients, were cultured on collagen gels until all cilia were lost, and then the cells were released in suspension as cell sheaths to form aggregates and vesicles. Cilia reappeared after 1 week. The number of ciliated cells increased progressively and within 1 month large areas of the aggregates were ciliated. These newly formed cilia were ultrastructurally normal. The ciliary activity as well coordinated and resulted in continuous movements of the aggregates in the culture medium. In the supranuclear cytoplasm the different ciliogenetic precursors were found: fibrogranular aggregates with occasionally small tubules, deuterosomes with procentrioles, kinetosomes, basal bodies, and short cilia. Initial stages of ciliary shaft formation, such as elevation of the apical membrane above the basal bodies without axonemal ultrastructure, could be well documented. The results indicate that in cystic fibrosis, ciliogenesis and the resulting ciliary activity in vitro are indistinguishable from those seen in cells from control tissue.
Cells, Cultured↗
Contribution of in vitro culture methods for respiratory epithelial cells to the study of the physiology of the respiratory tract.
Different techniques for culturing respiratory epithelial cells have been developed to overcome the limitations of studies on in vivo and on bioptic material. However, each culture technique has its limitations, specifically concerning the expression of differentiated properties. These methods and limitations are described and discussed. Special attention is given to recent developments, which may resolve some of the current problems.
Cells, Cultured↗
Ciliogenesis in cultured human nasal epithelium.
Human nasal epithelial cells, which lost their cilia in monolayer cultures, redeveloped cilia after 1 week in a suspension culture system. Before ciliogenesis started, the number of microvilli increased. Primary cilia were absent. The different cytoplasmic stages of this in vitro ciliogenesis could be reconstructed here into a sequence of events comparable to that described in the embryogenesis of the mammalian respiratory tract. In addition to the fibrogranular aggregates, deuterosomes with procentrioles and kinetosomes, small tubular structures in the fibrogranular aggregates could be visualized. The formation of the ciliary shaft above an aligned basal body started as an elevation of the apical membrane without any recognizable axonemal ultrastructure. This study provides the first full description of in vitro ciliogenesis on a human tissue.
Actin Cytoskeleton↗
Non-receptor-mediated refractoriness in prostacyclin production by human endothelial cells in a continuous flow system is delayed by a low-molecular-weight plasma fraction devoid of reducing cofactors for peroxidase-catalysed reactions.
Using a microcarrier perfusion model, we have investigated the effects of a low-molecular-weight plasma fraction (mol. wt. less than 10,000) on the capacity of human umbilical vein endothelial cells (HUVECs) to synthesize and release prostacyclin (PGI2) during repeated stimulation with either calcium ionophore A23187 or arachidonic acid (AA). This plasma fraction (filtrate 10,000), which has recently been shown to contain most of the activity previously referred to as 'prostacyclin regulating plasma factor', delayed the exhaustion of the PGI2 generating capacity of the HUVECs during repeated stimulation with either inducer. No such effect was seen with whole plasma. The PGI2 regulatory activity of the filtrate was not significantly affected by removal of reducing cofactors for peroxidase-catalysed reduction of hydroperoxides, accumulation of which inhibits cyclooxygenase. In contrast, albumin added to the filtrate abolished its protective effect on endothelial PGI2 synthesis. We conclude that low-molecular-weight plasma constituents partially preserve the PGI2-generating capacity of human vascular endothelium during repeated stimulation. Under continuous flow conditions, as applied in our study, this effect appears not to be related to reducing cofactor activity for peroxidase-catalysed reactions. In whole plasma, this PGI2 regulatory activity may be partially masked by the presence of plasma proteins.
6-Ketoprostaglandin F1 alpha↗