Biomedical subjects

E M Versteeg

Publications and source records attributed to E M Versteeg.

8 recordsLinked to original sources

PubMed2000

Restoration by vacuum inflation of original alveolar dimensions in small human lung specimens.

Resection of lung specimens results in deflated and distorted lung structures. If no major airway is present (as in the case of small lung specimens from biopsies), lung dimensions cannot be restored by inflation under 25 cmH20. This impedes morphological analysis of the tissue. This report describes a simple and easy procedure to restore alveolar dimensions in deflated small lung specimens. Small human lung samples were inflated using moderate vacuum conditions which are provided by a common water stream-driven vacuum device. Restoration of alveolar dimensions and morphology was evaluated for paraffin-embedded as well as frozen tissue, using morphometric and immunohistological analysis. Vacuum inflation results in restoration of original lung dimensions as judged by light and scanning electron microscopy, and by analysis of the mean linear intercept, and the average length, width, perimeter and surface area. It also results in markedly improved cutting characteristics, allowing reliable sectioning of 2 microm cryosections and achieving high resolution images in immunofluorescence. Vacuum inflation is a simple and easy procedure to restore lung architecture of small human lung specimens/biopsies with a concomitant improvement of cutting characteristics. It allows for correct histological analysis of small specimens which cannot be inflated otherwise.

Adult↗

PubMed1997

Induction of emphysematous lesions in rat lung by beta-D-xyloside, an inhibitor of proteoglycan synthesis.

The possible involvement of proteoglycans in the pathogenesis of emphysema was studied in rats by a single intratracheal instillation of p-nitrophenyl-beta-D-xylopyranoside (beta-D-xyloside), an inhibitor of proteoglycan synthesis. The first 3 days after instillation are characterized by mild hemorrhages, some infiltration of inflammatory cells, and edema. After 1 wk, lung morphology is normal again. Forty days after instillation, considerable parenchymal destruction has occurred as determined by the mean linear intercept (81 +/- 12 microns versus 57 +/- 5 microns for control [P < 0.001]). Pulmonary fibrosis is not observed. Instillation with p-nitrophenyl-alpha-D-xylopyranoside and p-nitrophenol do not induce parenchymal destruction, indicating the specificity of beta-D-xyloside action. Urinary glycosaminoglycan (GAG) content of the beta-D-xyloside-treated rats is increased 15-fold during the first day after instillation, mainly due to elevated levels of chondroitin sulfate and dermatan sulfate. The increase is correlated to the extent of parenchymal destruction after 40 days (r = 0.68; P < 0.002). At day 2 and thereafter, levels are normal again. A short-term increase in dermatan and chondroitin sulfate content is also observed in serum, bronchoalveolar lavage (BAL) fluid, and lung tissue. Heparan sulfate content is decreased in BAL fluid and lung tissue. Instillation with p-nitrophenyl-alpha-D-xylopyranoside and p-nitrophenol do not induce elevated GAG concentration in urine. We suggest that a disturbance in proteoglycan synthesis accompanied by an increase of (beta-D-xyloside-primed) free GAGs results in loss of stability and integrity of the alveolar wall, leading to parenchymal destruction and emphysematous lesions. beta-D-xyloside treatment may be an alternative experimental method for inducing emphysema.

Animals↗

PubMed1996

Altered composition of urinary heparan sulfate in patients with COPD.

In patients with emphysema the integrity of the extracellular matrix (connective tissue skeleton) is compromised. In this study we analyzed glycosaminoglycans, which are main constituents of this matrix, in urines from patients with chronic obstructive pulmonary disease (COPD)/emphysema. Glycosaminoglycans (GAGs) were purified by anion exchange chromatography and quantified using the 1,9-dimethylmethylene blue assay. Heparan sulfate (HS) was assayed using three different chemical methods: digestion with heparitinase or with nitrous acid and by use of an adapted 1,9-dimethylmethylene blue assay. A specific epitope on the HS molecule, defined by the monoclonal antibody JM403, was determined using an inhibition enzyme immunoassay. In patients with COPD total urinary glycosaminoglycan and HS content were not altered. The JM403 epitope of HS, however, was greatly decreased in patients (0.6 versus 4.1 units/mg creatinine for control subjects, p < 0.0001). A similar pattern was observed when patients with bronchial carcinoma with and without emphysema were compared (0.4 versus 2.4 units/mg creatinine respectively, p < 0.0005). Patients with sarcoidosis did not show a decreased epitope content. These results indicate a structural change or an altered processing of the HS molecule in patients with emphysema. Taking into consideration the importance of HS for the stability of the alveolar extracellular matrix, this change may be associated with the pathogenesis of emphysema.

Adult↗

PubMed1995

Elimination of autofluorescence in immunofluorescence microscopy with digital image processing.

Autofluorescence can be a very disturbing factor in immunofluorescence microscopy. We present here a method to eliminate autofluorescence. The method is based on the fact that most autofluorescent compounds have broad-banded excitation and emission spectra, whereas specific fluorescent probes have narrow spectra. Two images are recorded and digitized, one at a wavelength exciting both the fluorescent probe and the autofluorescent molecules, and one at a wavelength exciting only the latter. Subtraction of the autofluorescence signal from the total fluorescence signal, using a self-developed computer program, results in an autofluorescence-free image. The procedure is demonstrated for elimination of elastin-derived autofluorescence in human lung alveoli and for elimination of lipofuscin-derived autofluorescence in human heart muscle. The autofluorescence signal is positively correlated with tissue section thickness (r = 0.93; p < 0.0001), and can be used to correct the specific fluorescence signals for section thickness.

Adult↗

PubMed1995

Digestion of proteoglycans in porcine pancreatic elastase-induced emphysema in rats.

Pulmonary emphysema was induced in rats by a single intratracheal instillation of pancreatic elastase. The short-term effects of elastase instillation on basement membrane components were evaluated using immunohistochemical and biochemical methods. Lung alveoli showed a decrease in heparan sulphate proteoglycan content (especially of its heparan sulphate chains) 3 h to 7 days after induction. Type IV collagen, laminin and fibronectin were not affected. The glycosaminoglycan content of the lung was decreased during the first 3 days after induction, while the glycosaminoglycan concentration in urine was increased during the first 4 days by an increase of heparan sulphate and dermatan sulphate. The increase in urinary glycosaminoglycan content was positively correlated with the extent of emphysema developed after 40 days. We conclude that proteoglycans are target molecules for elastase, and may be involved in the pathogenesis of emphysema.

Animals↗

PubMed1994

A spectrophotometric method for the determination of heparan sulfate.

A simple and reliable spectrophotometric method for the determination of heparan sulfate is described. The method is based on the 1,9-dimethylmethylene blue assay for sulfated glycosaminoglycans. Addition of bovine serum albumin, together with a specific NaCl concentration and pH, results in a specific decrease of heparan sulfate-based absorbance. The amount of heparan sulfate can be calculated by subtracting the values obtained in the presence of albumin from those obtained in its absence. The sensitivity is 0.5 microgram heparan sulfate. Two applications are given: the quantification of heparan sulfate in urine, including urine from patients with mucopolysaccharidosis, and the evaluation of fractions from gel filtration and ion exchange column chromatography for isolation of heparan sulfate proteoglycans.

Glycosaminoglycans↗

PubMed1994

Quantification and characterization of glycosaminoglycans at the nanogram level by a combined azure A-silver staining in agarose gels.

A rapid, sensitive, and nonradioactive method has been developed for the quantification and characterization of glycosaminoglycans. The method is based on the separation of different types of glycosaminoglycans in agarose gel and subsequent fixation and staining with the cationic dye azure A, followed by silver enhancement. Densitometric analysis of the silver deposition gives a linear response between 1 and 20 ng for chondroitin and dermatan sulfate and between 2 and 40 ng for heparan sulfate. The detection limit is about 250 pg. The staining procedure was applied for the quantification and characterization of glycosaminoglycans in human serum, urine, and lung and in mouse kidney glomeruli. It requires only 10 microliters serum, 2 microliters urine, and only a single cryosection in case of tissue. The method is at least as sensitive as staining with radioactive markers and about 200 times more sensitive than conventional glycosaminoglycan-staining methods.

Animals↗

PubMed1992

Ultroser G and brain extract induce a continuous basement membrane with specific synaptic elements in aneurally cultured human skeletal muscle cells.

Basement membrane (BM) components were studied on human muscle and skeletal muscle cells cultured on different media by immunofluorescence and electron microscopy. Their topographical relation with acetylcholine receptors was investigated. Myotubes cultured on a combination of the serum substitute Ultroser G and brain extract show a continuous layer of heparan sulfate proteoglycans (HSPGs), laminin, and type IV collagen. In contrast, myotubes cultured on serum-containing media are associated with granular depositions of HSPG and laminin and only with wisps of type IV collagen. Omission of brain extract or substitution by chicken embryo extract results in an intermediate staining pattern. For all types of cultures, fibronectin is localized in and around mononuclear cells, but hardly associated with myotubes. A codistribution between clusters of acetylcholine receptors and HSPG and laminin and Vicia villosa B4 lectin-positive material exists only in Ultroser G/brain extract-based myotubes like in muscle in vivo. No clustering is observed in serum-based myotubes. Electron microscopy reveals that the former myotubes are surrounded by a continuous BM consisting of a lamina lucida, lamina densa, and lamina fibroreticularis. Proteoglycans are present on the external site of the lamina densa and associated in a regular fashion with collagen fibrils. In conclusion, BMs associated with myotubes cultured on Ultroser G/brain extract resemble in many ways the in vivo situation, including synaptic specializations. Cultured myotubes may serve as a model system for studies on the structure and function of human muscular (synaptic) BM under normal and pathological conditions.

Basement Membrane↗