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PubMed2006

Endoscopic ultrasound elastography-- a new imaging technique for the visualization of tissue elasticity distribution.

Endoscopic ultrasound (EUS) elastography is an imaging procedure used for the visualization of tissue elasticity during usual EUS examinations. EUS elastography can be accomplished real-time with state-of-the-art ultrasound systems, with the images being represented in transparent color superimposed on the conventional gray-scale B-mode scans. The aim of this review was to introduce the potential range of applications of EUS elastography. EUS elastography might be useful for the differentiation of benign and malignant lymph nodes, with a qualitative pattern analysis and a quantitative histogram analysis of the color images being used to adequately classify the lesions. Mapping of the tissue elasticity distribution might be useful for the differential diagnosis of focal pancreatic masses, especially in the setting of chronic pancreatitis where the accuracy of EUS-guided fine needle aspiration is also low. EUS elastography might also enhance the detection and differentiation of various solid tumors (adrenal tumors, submucosal tumors, etc.) situated nearby the gastrointestinal tract. Routine use of EUS elastography thus offers supplemental information that enhances conventional EUS imaging, with a possible decrease in the number of un-necessary EUS-FNA procedures used for tissue confirmation. However, future enhancements of the EUS elastography technology, as well as prospective, randomized studies will probably establish the clinical impact of dynamic elasticity imaging.

Diagnosis, Differential↗
PubMed2005

Tissue elasticity estimation with optical coherence elastography: toward mechanical characterization of in vivo soft tissue.

High-resolution imaging provides a significant means for accurate material modulus estimation and mechanical characterization. Within the realm of in vivo soft tissue characterization, particularly on small biological length scales such as arterial atherosclerotic plaques, optical coherence tomography (OCT) offers a desirable imaging modality with higher spatial resolution and contrast of tissue as compared with intravascular ultrasound (IVUS). Based on recent advances in OCT imaging and elastography, we present a fully integrated system for tissue elasticity reconstruction, and assess the benefits of OCT on the distribution results of four representative tissue block models. We demonstrate accuracy, with displacement residuals on the order of 10(-6) mm (more than 3 orders of magnitude less than average calculated displacements), and high-resolution estimates, with the ability to resolve inclusions of 0.15 mm diameter.

Angiography↗
PubMed1989

An experimental study on the effects of elastase, bleomycin and infection on the growth and tensile strength of elastic tissue in rabbit fetal membranes.

The effects of bleomycin, elastase and infection on the tensile strength of rabbit fetal membranes and the structure of the elastic tissue of rabbit amnion were studied. The experimental subjects were rabbits to which bleomycin (total dose, 20 mg) or elastase (total dose, 60 mg) was administered from 18 days of pregnancy. In addition to the fetal membranes from these treated animals, fetal membranes with amniotic infection induced by injection of Escherichia coli into the amniotic fluid (AF) of rabbits at 22 or 23 days of pregnancy were examined, and those from rabbits administered physiological saline solution were used as controls. The results obtained were as follows. Determination of tensile strength of the fetal membranes revealed that the infected membranes had minimum rupture pressure (18.67 +/- 6.30 mm Hg), followed by the elastase administration group (46.67 +/- 3.51 mm Hg). The value in the bleomycin administration group (99.67 +/- 12.89 mm Hg) was significantly higher than that in the control group (61.80 +/- 6.30 mm Hg). Histological changes in the fibroblast layer of these fetal membranes included elastic fibrosis due to excessive collagen production, which was mostly manifested as fibrosis densa, in the bleomycin administration group. In the elastase administration group, the elastic fibers were eliminated or became minute, as in the infection groups. The above results showed the adverse effects of elastase and bleomycin and the destructive effect of infection on the growth and properties of elastic tissue in the amnion, suggesting their pathophysiological importance.

Animals↗
PubMed1988

Is neutrophil elastase associated with elastic tissue in emphysema?

To test the role of elastase in the pathogenesis of emphysema human neutrophil elastase (HNE) was localised by electron microscopy using an immunogold staining technique. Specific localisation of HNE to elastic tissue in emphysema did not occur, but non-specific binding of immunoglobulin G (IgG) to elastic tissue in emphysematous and normal lung tissue, which was completely blocked by the non-immune serum that was homologous to the gold labelled second antibody, was found. HNE was also present, however, in the granules of neutrophils in the same sections. Non-specific labelling associated with elastin was probably due to binding of IgG to the high numbers of hydrophobic and charged regions known to be present in this molecule, and it is concluded that our findings do not support the existence of high concentrations of elastase in association with elastin in emphysematous lung tissue.

Aged↗
PubMed1997

The effect of chemosurgical peels and dermabrasion on dermal elastic tissue.

Chemosurgical peel is a technique that has been used widely by plastic surgeons and dermatologists to remove fine and deep wrinkles of the skin. However, the reaction of elastic tissue to the cutaneous application of commonly used chemical peeling agents has not been defined. This study comparatively assessed the alteration in dermal histology and mechanical properties of skin following treatment with 25% and 50% trichloroacetic acid, Baker's phenol solution, and dermabrasion. Yucatan minipigs served as the animal model. The skin was analyzed at five intervals over 6 months after treatment using histologic, quantitative, and mechanical analysis (hematoxylin and eosin, elastic tissue, and Sirius red stains, computerized digital morphometry, and a tensiometer). At 6 months we found no change in the quality, structure, or arrangement of elastic fibers in skin treated with a single application of 25% and 50% trichloroacetic acid or dermabrasion when compared with untreated skin. Skin treated with Baker's phenol solution showed a marked morphologic change in the elastic fibers. The fibers within the regenerated zone of dermis were sparse, wispy, and immature at 6 months after treatment. Preliminary tensiometric analysis of phenol-treated skin at 6 months indicated that the skin was stiffer and weaker. This study questions the possibility of long-term change to the skin by the deep penetration of caustic chemicals to remove wrinkles and rejuvenate the skin.

Animals↗
PubMed1977

Wrinkles due to idiopathic loss of mid-dermal elastic tissue.

Widespread areas of fine wrinkling of the skin had been noted for 2 years by a 42-year-old healthy white woman. Histological study disclosed a selective absence of elastic tissue strictly limited to the mid-dermis of the involved areas. It was postulated that an antecedent urticarial process may have led to such a specific zonal destruction of elastic tissue. The elastolytic process did not change or extend, and no urticarial lesions were seen during a year of observation.

Adult↗
PubMed2003

[Realtime elastography. A new ultrasound procedure for the reconstruction of tissue elasticity].

It is well known that some diseases, such as cancer, lead to a change of tissue hardness (i.e. the so-called elasticity modulus). The reconstruction of tissue elasticity provides the sonographer with important additional information which can be applied for the diagnosis of these diseases. Elasticity imaging has recently attracted attention as a technique which directly reveals the physical property of tissue and enables us to determine the change of tissue hardness caused by diseases. The elasticity modulus, i.e. the tissue elasticity distribution can be calculated from the strain and the stress of the examined structures. While the strain field can be estimated from the RF signals returned from tissue structures before and after compression, it is impossible to measure the stress field directly within the tissue. Another problem is that the compression of harder tissue structures is often followed by a lateral displacement of these structures. It is nearly impossible to represent the volume of this sideslip with conventional 2D methods but its calculation is indispensable for an accurate determination of the tissue elasticity of the examined structures. To overcome these problems, we propose the so-called Extended CA-method (Extended Combined Autocorrelation Method) which allows the reconstruction of the tissue elasticity of the examined structures on the basis of the 3-dimensional finite element model. The new technique enables a highly accurate estimation of the tissue elasticity distribution and the adequate compensation of sideslips. The realtime elasticity imaging described in this article, can easily be performed with the SonoElastography module that can be integrated into the platform of the HITACHI EUB-8500 system. Like colour Doppler examinations, tissue elasticity imaging can easily be performed with conventional ultrasound probes and does not require additional instruments (e.g. for measuring pressure or vibrations). The calculation of tissue elasticity distribution is performed in realtime and the examination results are represented in colour over the conventional B-mode image. The results of the simulations and phantom experiments performed verify that with the information obtained by the new realtime elasticity imaging method, lesions can be detected and represented more rapidly and with higher accuracy than with conventional methods based on the 2D Model, and that even lesions invisible on B-mode images can be detected.

Breast Neoplasms↗
PubMed2005

The tissue distribution of murine Abcc6 (Mrp6) during embryogenesis indicates that the presence of Abcc6 in elastic tissues is not required for elastic fiber assembly.

Mutations in the gene coding for the ABC transporter, ABCC6, in humans cause Pseudoxanthoma elasticum, which is characterized by the deposition of aberrant elastic fibers. To investigate whether the presence of ABCC6 in tissues synthesizing elastin is required for elastin deposition and elastic fiber assembly, we have compared the steady-state levels and tissue distribution of Abcc6 and tropoelastin mRNAs during mouse embryogenesis. Whereas tropoelastin mRNA levels rose during embryogenesis and were the highest in neonatal mice, Abcc6 mRNA levels remained constantly low throughout embryogenesis. In some tissues, both Abcc6 and tropoelastin mRNA were detected. However, Abcc6 mRNA and protein were not detected in neonatal aorta and arteries, which produce large amounts of elastin indicating that the presence of Abcc6 in elastic tissues is not required for elastic fiber assembly.

ATP-Binding Cassette Transporters↗
PubMed2004

Differential distribution of elastic tissue in human natural skin and tissue-engineered skin.

Tissue-engineered skins (TES), manufactured by epidermal and dermal equivalents, are now being used in biological, pharmacotoxicological and clinical applications. It is thus interesting to know to what extent artificial organs are similar to natural counterparts. Elastic fibres are important constituents of the extracellular matrix of natural skin (NS). The aim of our study was to investigate the possible occurrence and distribution of elastic tissue in a model of human TES using different histochemical techniques, including classical Orcein and Fuchsin-Resorcin methods and immunohistochemistry, at both light and electron microscopical levels. Immunoperoxidase and high resolution immunogold methods were used. In NS, classical staining techniques and elastin-immunohistochemistry revealed a well-organized network of elastic fibres. High resolution immunocytochemistry revealed an intense labelling in the amorphous component of elastic fibres. Fibres of different diameters were immunostained. In TES, no stained elastic fibres were observed using classical staining techniques, and the interpretation of immunoperoxidase observations was not clear-cut. In contrast, immunogold staining at the electron microscopical level provided specific labelling of elastin-like immunoreactive material in the dermal equivalent. However, ultrastructural immunocytochemistry revealed that elastic tissue organization in TES was poor compared to that in NS. This study demonstrates that elastic fibres are a component of the extracellular matrix in this model of TES and suggests that fibroblasts of the dermal equivalent are engaged in matrix secretion. Nevertheless, the level of extracellular matrix organization in TES is low compared to NS. Moreover, this study also suggests that different models of bilayered TES may differ with respect to extracellular matrix organization. These aspects should be considered when TES is used in biological and pharmacotoxicological studies. A better understanding of the factors influencing extracellular matrix formation in TES is necessary to achieve further development of skin generation in vitro.

Cells, Cultured↗
PubMed1981

Immunohistochemical comparison of ocular zonules and the microfibrils of elastic tissue.

Antibody to bovine zonules raised in rabbits gave diffuse staining of zonular fibrils with prominent accumulations at 35 to 45 nm sites of overbanding by means of the indirect immunoperoxidase technique. Antibody binding occurred in both fresh and paraffin-embedded material and was not species specific. The same pattern of heavy antibody binding and 35 to 45 nm periodicity was found on the microfibrils of elastic tissue in human and bovine ciliary body, calf ligamentum nuchae, and chick aorta. This cross reaction is the first direct evidence of a structural similarity or identity between components of the zonules and the microfibrils of elastic tissue, correlating with similarities in their morphology and amino acid profiles. Interstitial collagen fibers appear to have a minimal quantity of antigenically similar material at cross-banding sites. These relationships may hold important clues to the site of systemic involvement in connective tissue diseases associated with lens dislocation. Zonular antibody should prove useful in investigating abnormalities of the zonular-elastic microfibrillar system and cross-banding sites.

Animals↗
PubMed1987

The immunohistochemical localisation of microfibril-associated glycoprotein (MAGP) in elastic and non-elastic tissues.

We have previously identified the major antigen of elastin-associated microfibrils as a 31kD glycoprotein which we named microfibril-associated glycoprotein or MAGP. Affinity-purified antibodies to MAGP were shown to localise specifically to elastin-associated microfibrils in sections of bovine foetal nuchal ligament. In the present paper we compare the localisation of anti-MAGP antibodies and anti-tropoelastin antibodies in a range of bovine elastic and non-elastic tissues. The results show that anti-MAGP antibodies invariably localised to immuno-reactive elastic fibres, wherever they occurred. Extensive additional localisation was observed in a number of tissues. This extra distribution of anti-MAGP antibodies was found to correspond to those structures exhibiting the oxytalan histochemical staining reaction in tissues such as skin, periodontal ligament and ocular zonule. Since these oxytalan fibres have been shown to consist of 12 nm microfibrils which are morphologically similar to those of elastic fibres (and unpublished data from this laboratory confirm this conclusion), the results suggest that MAGP is a component of 12 nm microfibrils in both elastic and non-elastic tissues. Anti-tropoelastin antibodies did not localise to these oxytalan fibres, suggesting that tropoelastin is not a component of 12 nm microfibrils. MAGP was also detected in extracellular matrix regions of tissues such as skeletal muscle, Achilles tendon and spleen, suggesting that 12 nm microfibrils, containing one or more macromolecular constituents in common, make up an important structural system within the extracellular matrix in a wide range of elastic and non-elastic tissues.

Animals↗
PubMed1980

Pulmonary calcification and elastic tissue damage in pseudoxanthoma elasticum.

A case of pseudoxanthoma elasticum with extensive calcification and elastic tissue damage in the lung is described. This patient had classical skin changes, peripheral arterial calcification, and heart block, but no retinal changes. Hypercalcemia was excluded. Pulmonary involvement is in keeping with the concept of the basic abnormality being in the elastic fibres, and such involvement should be considered as a cause of respiratory symptoms in patients with this condition.

Arteries↗
PubMed1978

Studies of elastic tissue formation in the developing bovine ligamentum nuchae.

The foetal ligamentum nuchae showed two distinct stages of development, each characterised by its cell population and fibre products. Fibroblasts of the early phase have extensive ergastoplasm apparently associated with collagen production; those of the late phase have an "attenuated" cytoplasm and coincide with an increase of elastic tissue content. The elastic fibre comprised a core of fine elastin fibrils (100--130 nm diameter) and a surrounding mantle of microfibrillar protein. As development proceeded, the elastin fibrils appeared to coalesce with each other and also with elastin fibrils from adjacent fibres to form composite mature elastic fibre--a process which was accompanied by a loss of microfibrils. A characteristic of elastic fibres from adult ligament, not apparent in the foetal tissue, was that of bifurcation.

Animals↗
PubMed1980

Elastic tissue changes in skin following PUVA therapy.

Treatment of psoriasis with psoralens and high-intensity long-wave ultraviolet light (PUVA) produces changes in the ultrastructure of elastic tissue in skin. Early alterations consist of a loss of elastin followed by a breakdown of the microfibrils and subsequent fragmentation of the elastic fiber. Tissue examined 15 months after treatment was stopped still showed marked ultrastructural changes in the elastic fibers.

Elastic Tissue↗
PubMed1998

Mechanical role of elastin-associated microfibrils in pig aortic elastic tissue.

The contribution of microfibrils to the mechanical performance of the meshwork of elastic tissue in mature pig aorta was investigated by comparing the properties of autoclaved tissue containing elastin and microfibrils with autoclaved tissue that had been treated with dithiothreitol (DTT) or hot alkali to remove the microfibrils from the elastin. The uniaxial tensile stress-strain curve of the autoclaved tissue was linear to a strain of 0.6 or 0.7 and increased nonlinearly up to the breaking strain. The nonlinearity at high strains could not be accounted for by nonGaussian behavior and was attributed to the progressive alignment of the elastic fibers with strain. Removal of the microfibrils with DTT or treatment with calcium reduced the modulus at low strains by 12% and 4% respectively and increased the modulus at high strains, suggesting that the microfibrils have the capacity to change the orientation of the elastin fibers, possibly transmitting some of the load from one elastin fiber to another. Our findings suggest two possible roles for the microfibrils in vivo: distributing the load throughout the elastic fibers of the arterial wall and direct load bearing. The modulus and the breaking stress of the rings decreased linearly with the duration of alkali treatment starting immediately. By 45 min the modulus had dropped by 30% and the breaking stress by 50%, even though the amino acid content of the extract gave little evidence of elastin hydrolysis. Alkali treatment should not be used on autoclaved pig aortic tissue to be used for mechanical testing.

Actin Cytoskeleton↗
PubMed1978

The identification of glycoproteins associated with elastic-tissue microfibrils.

Cell cultures derived from foetal bovine ligamentum nuchae accumulate extracellular fibrils morphologically identical with elastic-tissue microfibrils. Two glycoproteins synthesized by the ligament cells are closely related to the matrix microfibrils as assessed by immunological and chemical extraction techniques.

Animals↗
PubMed1987

Three-dimensional architecture of elastic tissue in athero-arteriosclerotic lesions of the rat aorta.

The overall three-dimensional architecture of elastic tissue in athero-arteriosclerotic lesions of the ascending aorta of the rat was studied, using scanning electron microscopy (SEM), after hot-formic acid extraction followed by a freeze-drying method. The lesions were induced by feeding the rats a diet containing 2% cholesterol for 6 weeks and administering massive doses of vitamin D2 for the first 4 days. SEM revealed the synthesis of elastins mainly in the intima and the degradation in the internal elastic lamina (IEL) and medial concentric elastic lamellae. Intimal elastic elements involved in atherosclerotic lesions were composed of an intricately tangled network of fibrous elastins or a row of elastic laminae that surrounded many rectangular compartments, which were separated by fenestrated septum-like elastins and were assumed to be the sites of smooth-muscle-cell proliferation. These observations indicated remodelling of the elastic laminae in the intima. Degradation in the IEL and media was attributed to either vitamin D2 intoxication, which was characterized by the formation of a large degraded portion, or an enhanced elastolytic process. These alterations of elastic elements probably reflect the exact frame of the modes of migration of aortic smooth muscle cells in the development of athero-arteriosclerotic lesions, thereby indicating the role of smooth muscle cells in the progress of atherosclerosis.

Animals↗