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At least 145 records · Page 8Linked to original sources
PubMed2003

Breaking strength and tissue elasticity after Shouldice repair.

There are few objective studies in the surgical literature on the strength of an inguinal hernia repair during the immediate postoperative period. To provide the relevant advice and recommendations on physical activities during the period of convalescence, a study on the strength of the Shouldice repair was carried out. Twenty-eight Shouldice repairs were performed on 17 fresh human cadavers (11 male, 17 female, mean age 79.9+/-6.2 years). Following the excision of the transversalis fascia, the breaking strength and tissue elasticity were measured using an automated test device. All tissue ruptures occurred outside the limits of the Shouldice repair. Mean breaking strength was 53.9+/-20.1 N, showing no significant differences between males and females. The measured overall elasticity of tissue samples was 4.6+/-2.3 N/cm. Again there was no marked difference between genders. However, breaking strength and elasticity were found to be significantly affected by age. The Shouldice repair demonstrated a higher tensile strength when compared to the surrounding tissue. Strength after a Shouldice repair of the floor of the inguinal canal was found to be several times higher than could be attained under physiologic conditions. Therefore, an early postoperative return to normal activity can be recommended.

Aged↗
PubMed1999

Deformation simulation algorithms of elastic tissues in "real-time" based in elasticity theory.

In this paper, a new deformable model based in Boundary Elements Method (BEM) is presented. This model is characterised by its robustness and high deformation calculation speed. Experiments developed show that this model could calculate elastic deformations of elastic objects composed by 150 nodes with a 15 Hz. refresh rate (minim refresh rate acceptable in real time interactive systems).

Algorithms↗
PubMed1982

An elastic tissue defect in dermatofibrosis lenticularis disseminata. Buschke-Ollendorff syndrome.

A patient with dermatofibrosis lenticularis disseminata (Buschke-Ollendorff syndrome) was found to have a distinctive abnormality of the cutaneous elastic tissue. This abnormality, studied by histochemical and ultrastructural techniques, was characterized by the presence of hyalinized, thick fibers that entrapped normal bundles of collagen. Histochemically, these fibers stained like elastin but showed certain tinctorial characteristics of pre-elastin. Ultrastructurally, this elastin-like substance was composed of large clumps of electron-dense material with a fine fibrillar coating. The changes were sufficiently distinctive to be diagnosed by light microscopy.

Collagen↗
PubMed1988

Immunohistochemical studies on vitronectin in elastic tissue disorders, cutaneous amyloidosis, lichen ruber planus and porphyria.

Vitronectin, identical with serum-spreading factor and S-protein of complement, is a glycoprotein present in both plasma and tissue. It stimulates cell adhesion and spreading and affects the complement and coagulation pathways. Vitronectin immunoreactivity was recently found in conjunction with dermal and renal elastic fibres, in renal amyloid deposits in cases of AL- and AA-amyloidosis, and in sclerotic glomerular lesions. Skin specimens from lesions of patients with selected skin diseases were investigated with an avidin-biotin peroxidase technique using both monoclonal and polyclonal anti-vitronectin antibodies and an alkaline phosphatase anti-alkaline phosphatase technique using monoclonal anti-vitronectin antibodies. Vitronectin immunoreactivity was found in association with the abnormal elastic tissue in solar elastosis and pseudoxanthoma elasticum. It was also found in conjunction with dermal amyloid deposits in primary localized cutaneous amyloidosis and in Civatte bodies in cases of lichen ruber planus. In cases of erythropoietic protoporphyria and porphyria cutanea tarda, hyaline perivascular deposits also demonstrated positive vitronectin immunoreactivity. The presence of vitronectin immunoreactivity not only in normal and degenerated elastic fibres but also in various pathological tissue deposits suggests that vitronectin occurs both in elastic fibres and in different types of abnormal protein deposits.

Amyloidosis↗
PubMed1992

Ocular and cutaneous manifestations of heritable disorders of collagen and elastic tissue.

Ocular and cutaneous stigmata are hallmarks of the heritable disorders of collagen and elastic tissue. Awareness of the oculocutaneous features is essential both to aid diagnosis and to direct management of affected patients. Although the angioid streaks of PXE, blue sclerae of OI, ocular fragility of EDS and ectopia lentis of Marfan syndrome are the best-known ocular signs of these disorders, other relevant ophthalmologic symptoms often accompany such classic findings.

Collagen Diseases↗
PubMed1994

Stress-dependent finite growth in soft elastic tissues.

Growth and remodeling in tissues may be modulated by mechanical factors such as stress. For example, in cardiac hypertrophy, alterations in wall stress arising from changes in mechanical loading lead to cardiac growth and remodeling. A general continuum formulation for finite volumetric growth in soft elastic tissues is therefore proposed. The shape change of an unloaded tissue during growth is described by a mapping analogous to the deformation gradient tensor. This mapping is decomposed into a transformation of the local zero-stress reference state and an accompanying elastic deformation that ensures the compatibility of the total growth deformation. Residual stress arises from this elastic deformation. Hence, a complete kinematic formulation for growth in general requires a knowledge of the constitutive law for stress in the tissue. Since growth may in turn be affected by stress in the tissue, a general form for the stress-dependent growth law is proposed as a relation between the symmetric growth-rate tensor and the stress tensor. With a thick-walled hollow cylinder of incompressible, isotropic hyperelastic material as an example, the mechanics of left ventricular hypertrophy are investigated. The results show that transmurally uniform pure circumferential growth, which may be similar to eccentric ventricular hypertrophy, changes the state of residual stress in the heart wall. A model of axially loaded bone is used to test a simple stress-dependent growth law in which growth rate depends on the difference between the stress due to loading and a predetermined growth equilibrium stress.

Bone Development↗
PubMed1978

Resolution and repair of elastic tissue calcification in pseudoxanthoma elasticum.

Biopsy specimens of a skin lesion from a patient with pseudoxanthoma elasticum were obtained at the beginning and end of a 1 1/2-year period of clinically documented regression of the lesion. Light microscopic studies of these specimens showed that, during the period of regression, there was a decrease in the number of abnormal calcified elastic fibers in the dermis. Electron microscopic findings were interpreted as indicating breakdown and removal of mineralized elastic fibers at the beginning and formation of new elastic fibers at the end of the regression period. Cytoplasmic processes of active fibroblasts were intimately associated with fibers undergoing dissolution. The case thus represents a clinically and morphologically documented example of resolution and repair of elastic tissue calcification.

Biopsy↗
PubMed1993

Penicillamine-induced changes in elastic tissue of the upper respiratory tract.

We describe a patient who developed upper respiratory tract symptoms following long-term treatment of Wilson's disease with penicillamine. These symptoms were attributed to areas of pharyngeal thickening and were treated with a laser. Histological examination of the lesions showed proliferations of abnormal elastic fibres similar to those previously described at other sites, especially the skin, in patients receiving penicillamine. This drug impairs the maturation and reduces the stability of elastic fibres and although elastic tissue throughout the body is affected, we are aware of no previous reports of penicillamine-induced changes presenting with upper respiratory tract symptoms.

Back↗
PubMed1976

An evaluation of elastic tissue staining.

The Special Procedures Laboratory of the Department of Pathology at M.D. Anderson Hospital was concerned with the nationwide shortage of hematoxylin. The amount of this dye required for various staining solutions was calculated to determine thrifty usage. Some solutions required more hematoxylin than was available and prompted the serious investigation of existing techniques and new methods for routine laboratory use. Evaluation of various techniques resulted in a significantly successful modification of Gomori's aldehyde fuchsin technique, which was subsequently adopted as a routine procedure for elastic tissue staining in the Special Procedures Laboratory.

Aldehydes↗
PubMed1986

Staining of elastic tissue by Verhoeff's iron hematoxylin.

The elastic system of normal human skin was studied by light and immunofluorescence. Oxytalan, elaunin et elastic fibers were stained by weigert, orcein, gomori and Verhoeff. By Verhoeff's method all elastic system of dermis is shown, with other three stains, only elaunic and elastic fibers are well visualized. These results are confirmed by immunofluorescence studies.

Adult↗
PubMed1981

Studies on elastic tissue of aorta in aortic dissections and Marfan syndrome.

Insoluble elastins were isolated from control and aneurytic aortas by a sequential extraction procedure involving the use of purified collagenase. Marked differences in amino acid analyses and susceptibilities to pancreatic elastase were observed between normal and pathological samples. The incorporation of either 14C-lysine or 14C-glucosamine into proteins of the vessel wall was also studied. In addition, high amounts of elastase-type activity was extractable from pathological aorta specimens which may contribute significantly to the loss of elastic tissue evidenced by ultra-structural studies and confirmed by the biochemical technics. We propose therefore that increased elastase-type protease activity in these pathological aortas does significantly contribute to the weakening of the aortic wall and also may well be the main cause of the rupture of aneurysms observed occasionally.

Adult↗
PubMed2001

Magnetic resonance elastography: non-invasive mapping of tissue elasticity.

Magnetic resonance elastography (MRE) is a phase-contrast-based MRI imaging technique that can directly visualize and quantitatively measure propagating acoustic strain waves in tissue-like materials subjected to harmonic mechanical excitation. The data acquired allows the calculation of local quantitative values of shear modulus and the generation of images that depict tissue elasticity or stiffness. This is significant because palpation, a physical examination that assesses the stiffness of tissue, can be an effective method of detecting tumors, but is restricted to parts of the body that are accessible to the physician's hand. MRE shows promise as a potential technique for 'palpation by imaging', with possible applications in tumor detection (particularly in breast, liver, kidney and prostate), characterization of disease, and assessment of rehabilitation (particularly in muscle). We describe MRE in the context of other recent techniques for imaging elasticity, discuss the processing algorithms for elasticity reconstruction and the issues and assumptions they involve, and present recent ex vivo and in vivo results.

Acoustics↗
PubMedDate not supplied

Actinically degenerate elastic tissue: the prime antigen in the giant cell (temporal) arteritis syndrome? New data from the posterior ciliary arteries.

OBJECTIVE: To search for evidence of actinic elastotic degeneration (actinic arteriopathy) and giant cell arteritis (GCA) in the posterior ciliary arteries of eyes from aged white Australians. METHODS: Three hundred donor eyes were given to us by the Lions Eye Bank of New South Wales at Sydney Hospital. Of these, 146 formed the basis of this study. Portions of the posterior ciliary arteries located in relation to the optic nerve heads were processed in paraffin and were then stained by a sensitive haematoxylin and eosin stain that had been especially developed to display actinic elastotic degeneration of elastic tissue. RESULTS: Among 60 "aged" subjects (70-90 yrs.), a total of 41 (approximately 68%) showed definite changes of actinic elastotic degeneration in their laminae, a condition called actinic arteriopathy. One of these subjects revealed giant cells on degenerate lamina, giving a picture regarded as early (pre-clinical) GCA. A young "control" group of 60 subjects 17-59 years of age revealed only one subject with a similar degree of actinic arteriopathy. CONCLUSIONS: Actinic arteriopathy of the posterior ciliary arteries was more frequent and advanced in the "aged", over-70 group as compared with changes in the "young" group < 60 years of age. One aged subject without a history of eye disease showed giant cells associated with elastotically degenerate internal elastic lamina. Her fortuitous lesions are regarded as indicative of how GCA is likely to begin in the damaged arteries.

Adolescent↗
PubMed1980

Isolation of elastic tissue microfibrils derived from cultured cells of calf ligamentum nuchae.

Cells cultured from calf ligamentum nuchae produce extracellular microfibrils identical to those of intact elastic tissue as determined by ultrastructural appearance, degradative enzyme susceptibilities and amino acid composition. A method to isolate large amounts of the microfibrillar component using fluorescein mercuric acetate is described. The cultures do not appear to synthesize the amorphous component, elastin, in that radioactive desmosine and isodesmosine were not detected after incubating cultures with labeled lysine nor was elastin seen ultrastructurally.

Amino Acids↗