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PubMed1989

The thickness, shape and arrangement of elastic fibres within the nuchal ligament from various animal species.

As shown by statistical evaluation carried out within various animal species (e.g. ruminants, equids, carnivores and proboscidates) the thickness of elastic fibres of the nuchal ligament is a specific character, i.e. unrelated to the somatic size of taxonomically different specimens. On the whole, ruminants are characterized by thicker elastic fibres than those from equids and carnivores. Moreover, within ruminants a correlation between the thickness of elastic fibres and body size has consistently been found. However, this condition occurs only when comparison between zoologically related species is drawn. During postnatal growth clearcut structural changes were brought to light, represented by the following phenomena simultaneously taking place: a) increase in thickness and lenght of preexisting elastic fibres; b) a progressive increase in the number of fibre splittings as well as of collaterals given off by individual fibres along their extension; c) neoformation of elastic fibres, and their addition to preexisting ones. In the bovines, already at six months of postnatal life, the elastic fibres of larger caliber have attained their full size.

Animals↗
PubMed1988

Scanning electron microscopy of elastic networks from the bifurcation region of guinea pig carotid arteries.

We isolated the elastic network from the bifurcation region of guinea pig carotid arteries by treatment with hot alkali and examined its adventitial and adluminal components by SEM. The thickness of networks from common and external carotid arteries averaged 87.5 microns (+/- 6.9 SD) and from the carotid sinus averaged 46.8 microns (+/- 2.4 SD). The networks consisted of a mesh of elastic tissue that became a continuous sheet, 2 microns thick, which formed the internal elastic lamina (IEL). The IEL was fenestrated; the perforations varied in number among the vessels (occipital greater than carotid sinus greater than common = external carotid), and some were spanned by delicate elastic fibers. The IEL's adluminal surface was a smooth membranous sheet, which in some specimens bore unidirectional loose fibers, or was composed of tightly fused bundles of uni- or multidirectional fibers. The interior region of the cranial carotid sinus contained unique blister-like structures and dense clusters of fenestrations, together with a honeycomb-like mesh near the ascending pharyngeal artery. The outer, adventitial elastic layer consisted of a network of loose elastic fibers that were fused with the inner layers. We conclude that the structural differences noted among the common and external carotid arteries and carotid sinus are related to the sinus's unique pressure-sensing functions.

Animals↗
PubMed1987

[Diffuse disease of elastic tissue and hyperphosphoremia].

Pseudoxanthoma elasticum (PXE) is exceptionally associated with abnormal phosphate-calcium metabolism. On the other hand, significant hyperphosphataemia is present in tumoral calcinosis, with an occasional elastopathy resembling that of PXE. We report here the first case of diffuse elastic tissue disease associated with hyperphosphataemia in the absence of tumoral calcinosis. The patient, a 29-year old Gabonese, had severe arteritis of the lower limbs with linear calcifications of the aorta and major arteries of the limbs. Angioid streaks and calcifications were present in the retinas. The skin appeared to be normal, but histological examination of specimens from flexures showed abnormalities of the elastic tissue with many fibres being broken into small pieces and curled up. In a morphometric study of cutaneous elastic tissue these abnormalities were compared with those observed in a PXE patient and with normal elastic tissue. The abnormalities in our patient and in the PXE patient were similar. Compared to normal elastic tissue, there was a slight decrease in the total number of oxytalan and elaunin fibres. The elastic fibres were distinctly wider, longer and separated from each other by smaller spaces, but not more numerous than normally. The histopathological appearance of an artery removed during bypass surgery was similar to that of a PXE artery. The hyperphosphataemia was due to an increase in tubular absorption of phosphates without abnormalities of parathyroid hormone, or resistance to its phosphaturic effect or any other tubular disorder. It was little altered by aluminium carbonate, and it partially decreased after addition of calcitonin.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Altered skin elastic fibers in hypothyroid myxedema and pretibial myxedema.

Elastic fibers account for 2% of dermal volume and are responsible for normal skin resiliency. We investigated a disorder of the dermal elastic component as the mechanism for the decreased elasticity of skin in myxedema. Skin biopsy specimens were obtained from patients with thyroid diseases and normal subjects matched for age, sex, and biopsy location. Elastic fiber concentration, determined by computerized morphometric analysis of Verhoeff-van Gieson-stained sections, was significantly lower than normal in hypothyroid and pretibial myxedema. The decreased elastin concentration was not a consequence of the glycosaminoglycan infiltration. Ultrastructural studies of myxedematous skin showed wide variability of elastic fiber diameter and decreased microfibrils. Myxedema (hypothyroid and pretibial) is consistently associated with quantitative and qualitative defects of dermal elastic fibers.

Adult↗
PubMed1975

[Formation of elastic fibers around basal cell carcinomas: light microscopical observations (author's transl)].

From 275 specimens of all sorts of basal cell epitheliomas the new formation of elastic fibers was histologically investigated by means of selective elastic tissue stains such as orcein and resorcinfuchsin. In nearly one third of the basal cell epitheliomas newly formed elastic fibers could be observed in the stroma. In places where a new formation of elastic fibers was demonstrated fibroblasts and mast cells (toluidine blue stain) were unusually numerous. Apparently the influence of the growing tumor masses of basal cell epitheliomas leads to a dermo-epidermal interaction in the form of 1. increase of mast cells 2. stimulation of fibroblasts 3. new formation of elastic fibers. The observation suggest that there exists a relationship between the above noted findings. Due to the dermo-epithelial interaction (even in senile skin) in the stroma of basal cell epithelioma fibroblasts can be stimulated to such a degree that they regain the ability to produce elastic fibers-a function which usually is greatly diminished with increasing age. The findings seem to be important from the view point of rejuvenation of aging human skin.

Adult↗
PubMed1984

The effect of agarose and dexamethasone on the nature and production of extracellular matrix components by elastic cartilage chondrocytes.

Chondrocytes isolated enzymatically from rabbit ear cartilage, were cultivated in vitro in the presence of 2% agarose or 0.1 mumol/l dexamethasone. Freshly-isolated chondrocytes suspended in either Eagle's medium or 2% agarose were auto-transplanted intramuscularly. Samples were then examined by light microscopy and transmission electron microscopy. The cells cultivated in vitro rapidly formed confluent multiple overlapping layers filled with a loose matrix consisting of single collagen fibres, proteoglycans and scarce elastic fibres. The number and maturity of the elastic fibres increased substantially after dexamethasone was added. The chondrocytes in intramuscular transplants produced a larger amount of intercellular matrix with many elastic fibres than those cultured in vitro. Addition of agarose to in vitro and in vivo systems selectively suppressed the elastin production but did not diminish the production of elastic fibre microfibrils and other matrix components. This made cultures and transplants of elastic chondrocytes resemble rather hyaline cartilage than the original tissue. It seems that the lack of elastin in the matrix does not result simply from inhibition of elastin secretion or increased elastolysis. It may be related to a reversible change of genetic expression of elastic cartilage chondrocytes under the influence of agarose.

Animals↗
PubMed1982

Periductal elastic tissue of breast cancer. Quantitative histologic study.

Using techniques of stereology, we estimated the relative volume of periductal elastic tissue in 60 infiltrating ductal carcinomas of the breast. Volume density of periductal elastic tissue in the neoplasm correlated with our own subjective histologic estimates of the amount of elastic tissue. Periductal elastic tissue had a significantly higher volume density in the neoplasm than in nonneoplastic breast, but the two estimates did not correlate with each other. Similarly, the volume density of elastic tissue in the neoplasm did not correlate with that of neoplastic cells or of stromal collagen in the neoplasm, degree of lymphocytic infiltration, lymph node metastasis, mortality, menstrual status, age, parity, or presence or levels of estrogen receptor protein in the neoplasm. On the other hand, parity correlated with the volume density of periductal elastic tissue in the nonneoplastic parenchyma of the breast. Our findings indicate that there are at least two separate elastogenic effects in infiltrating ductal carcinoma of the breast: that exerted by parity on nonneoplastic tissue and that exerted by cancer itself on the neoplasm.

Adult↗
PubMed1982

The elastic system in the thymus of the opossum Didelphis marsupialis aurita.

The author studied the elastic system of fibers in the thymus of the opossum. 2 types of fibers were found: elastic and oxytalan. The elastic fibers form a dense network at the periphery of thymic capsule, while a delicate meshwork of oxytalan fibers is found at the inner part of the capsule, being connected to the elastic plexus by some elastic fibers which cross the whole thickness of the capsule. Within thymic trabeculae only oxytalan fibers were observed. The peculiar arrangement of the elastic system of the thymus perhaps allows the organ to be exposed to mechanical shocks without transmitting such stress to the thymic parenchyma.

Animals↗
PubMed1982

The distribution and arrangement of elastic fibres in the intervertebral disc of the adult human.

Selected cervical and thoracic intervertebral discs were removed from twelve human adults at autopsy. The discs were prepared by the paraffin method, stained with orcein or by Verhoff's technique and examined with the light microscope for the presence of elastic fibres. Elastic fibres were located only in the lamellae of the anulus fibrosus and the superficial zones of the nucleus pulposus from regions of intervertebral disc that connected or interfaced with osseous vertebrae. Elastic fibres were longitudinally, circularly and obliquely arranged in lamellae of the anulus fibrosus and penetrated bony vertebrae as Sharpey's fibres. Elastic fibres assumed a three dimensional lattice work in the superficial zone of the nucleus pulposus and connected it to the hyaline cartilage end plate as Sharpey's fibres. Irregularly arranged elastic fibres interconnected the superficial zone of the nucleus pulposus and lamellae of the anulus fibrosus. Elastic fibres were a major histological component of the ligamenta flava and anterior longitudinal ligaments.

Aged↗
PubMed1994

Arrangement of elastic fibres in the integument of domesticated mammals.

The hairy skin of important domesticated mammals (12 species) was studied with scanning electron microscopy, transmission electron microscopy, laser scanning microscopy, and several light microscopical methods, to obtain more information about three-dimensional elastic fibre arrangement. It was obvious that there is a basic construction scheme of the elastic fibre meshwork as present in the upper and mid-dermis, with special regard to the size, number, and grouping of hair follicles. In the densely-haired species, in particular, a typical elastic mat with horizontal fibres is formed. In many of the sparsely-haired animals, the upper and mid-dermis show a sponge-like elastic system. In the rather massive, collagen-rich skin of large species, the lower two thirds of the dermis without hair follicles only possess a loosely-structured elastic network, but thick elastic sheets are found at the border zone with the hypodermis. Specific features appear with regard to the type of mechanical strain exerted, different body regions, varying hair follicle density, or as connected with the anchoring of the hair follicle complex, blood vessels, and nerves.

Animals↗
PubMed1994

Age-related distribution of elastic fibers in the rabbit knee.

The distribution and histochemical properties of elastic fibers in the knee of newborn, young, adult, and old New Zealand White rabbits were studied. In the growing rabbit, elastic fibers, especially oxytalan fibers, are abundant in the perichondrium and the fibrous layer of the periosteum. They are homogeneously distributed in tendons, ligaments, and menisci, and are absent in the epiphyseal cartilage and growth plate and at the enthesis. In mature rabbits, the articular capsule, the synovial membrane, the peritenon, the periosteum, the perimysium, and the perivascular connective tissue are rich with elastic fibers. They are rarer in the tendon and are absent at the enthesis, in bone and articular cartilage. In the meniscus, the fibers are distributed centripetally. The distribution of elastic fibers is probably related to the different functional role and biomechanical behavior of each tissue. Finally, the type of elastic fiber in the various tissues changes with age; younger animals have more oxytalan fibers than adult animals. A gradual process of maturation and specialization of the network of elastic fibers takes place with age.

Aging↗
PubMed1993

Relationship between magnesium and elastic fibres.

The presence of magnesium was demonstrated by histochemical methods in elastic fibres from different locations. After pretreatment with elastase a positive reaction could no longer be detected. Microfibrils which enclose the elastin core of the elastic fibres gave no positive reaction. These results support the supposition of a close relationship between Mg and elastin. Determination of the Ca/Mg ratio by atomic absorption spectrometry in variants of fibrous connective tissue showed a decreasing Ca level with increasing elasticity. The Ca/Mg ratio in lattices containing rubber-like particles disclosed striking diminution of Ca. These data support the speculation that the antagonism of Mg to Ca plays a fundamental role in the maintenance of elasticity. The special interaction of the Mg2+ ion with water molecules is very probably a further prerequisite for elasticity in natural elastic materials.

Calcium↗
PubMed1993

The elastic yield stress of human blood.

The elastic yield stress is a key parameter in the way human blood flows, because after yielding the microstructure formed by the red cells undergoes a dramatic change and the blood is transformed to a superfluid state. This yielding of the structure is revealed in measurements of the progressive changes in viscoelasticity with increasing amplitude of oscillatory flow. Measurements of the magnitude and phase of the pressure differential along the tube length, and the volume flow through the tube, are performed with sinusoidal oscillatory flow in a cylindrical tube at a frequency near that of the normal pulse rate. This gives the shear rate, shear strain, and the viscous and elastic components of shear stress at the tube wall, and from these parameters the viscosity and elasticity of the blood are calculated. The instrumentation (Vilastic Scientific Inc.) used to perform these measurements produces graphs of the viscous and elastic shear stress versus the shear strain. Near unit strain the elastic stress reaches a maximum, marking the point at which the quiescent aggregated cell structure yields and reassembles into a layered structure. Examples are given to show how factors such as red cell aggregation and cell deformability affect the elastic yield stress.

Blood Physiological Phenomena↗
PubMed1996

Distribution and appearance of elastic fibers in the dermis of clinically normal dogs and dogs with solar dermatitis and other dermatoses.

OBJECTIVE: To determine the distribution and amount of elastic fibers in the dermis of clinically normal dogs and dogs with dermatoses, particularly solar dermatitis. DESIGN: Skin specimens from 7 anatomic sites were obtained from 19 clinically normal dogs after euthanasia to evaluate the normal distribution of elastic fibers. Biopsy specimens also were obtained from 34 dogs with dermatoses, including 16 with solar dermatitis. Tissue sections were stained with H&E, Verhoeff-van Gieson, and periodic acid-Schiff. ANIMALS: 19 clinically normal dogs and 34 dogs with dermatoses. PROCEDURE: Numbers of elastic fibers were graded subjectively. Comparisons between clinically normal dogs and dogs with dermatoses were made. RESULTS: Normal elastic fibers were present in low numbers in the dermis of adult dogs, regardless of anatomic site or presence or severity of dermatitis. Condensed elastotic material was visualized in only 2 dogs with solar dermatitis. In both dogs, the elastotic material was Verhoeff-van Gieson and periodic acid-Schiff stain positive but was not visible with H&E stain. The most frequent histopathologic finding in the dermis of dogs with solar dermatitis was superficial dermal fibrosis. CONCLUSIONS: The dermis of clinically normal dogs does not contain abundant elastic fibers. Alterations of elastic fibers in dogs with solar dermatitis are rare. Superficial dermal fibrosis may be a better indicator of solar damage.

Animals↗
PubMed1996

Generalized acquired cutis laxa associated with coeliac disease: evidence of immunoglobulin A deposits on the dermal elastic fibres.

Acquired cutis laxa (ACL) is an uncommon elastolytic disorder of unknown aetiology. In rare instances, ACL has been reported in association with autoimmune diseases and dermal deposit of immunoglobulins, suggesting that destruction of elastic tissue may be immunologically mediated. We report a 35-year-old man with generalized acquired cutis laxa (GACL) associated with a persistent papular erythematous eruption that histopathologically showed some resemblance to dermatitis herpetiformis. A marked reduction and degeneration of dermal elastic fibres was noted in biopsies from loose-hanging skin. Direct immunofluorescence from non-inflammatory loose skin revealed granular immunoglobulin A (IgA) deposits at the basement membrane zone and fibrillar IgA deposits in the dermal papillae. IgA deposits were also observed on the elastic fibres of the reticular dermis. Electron microscopy of skin from the submammary fold revealed fragmented elastic fibres, partial absence of peripheral microfibrils and abundant neutrophils, some of which were degranulated and adjacent to elastic fibres. Immunoelectron microscopy of an erythematous papule revealed IgA deposits around dermal elastic fibres. Antigliadin, antireticulin and antiendomysium antibodies were present. Jejunal biopsies showed a gluten-sensitive enteropathy. A possible IgA-mediated immune mechanism for the development of GACL in our patient is suggested.

Adult↗
PubMed1995

Age-related changes in the elastic properties of the aortic tree in normotensive patients: investigation by intravascular ultrasound.

The arterial wall structure degenerates with increasing age, elastin fibers decrease while collagen increases. We investigated the elastic properties of the aorta and iliac arteries to determine the relationship between aging and arterial mechanics. The regional elasticity of the aorta and iliac arteries was determined at five different sites in 40 normotensive patients aged 32 to 78 years. A combined procedure for arterial blood pressure measurement and arterial cross-sectional area determination was employed to calculate the parameters of compliance and pulse wave velocity. The descending thoracic and abdominal aorta showed significant correlations between age and elasticity. No correlation was observed at the aortic bifurcation. A significant correlation between age and pulse wave velocity was apparent in the common iliac artery, whereas compliance showed no significant correlation to age. In the external iliac artery as well, no significant correlation between age and elasticity could be found. Arterial elasticity decreases with age, but this process does not progress uniformly at all sites of the arterial system. The difference in elasticity between these basic types of arteries diminishes throughout life. At the aortic bifurcation, mechanical aging seems to proceed faster than at unbifurcated arterial segments.

Adult↗
PubMed1997

Finite elasticity formulations for evaluation of ligamentous tissue.

The variety of techniques used to measure the cross-sectional area of soft connective tissues during mechanical testing lead to inconsistencies in elastic descriptions. This study compares the numerical differences between finite elasticity (Eularian and Lagrangian formulations) and infinitesimal elasticity when considering stress, strain and elastic modulus of ligamentous tissue. Our results found stress differences (Cauchy versus Kirchhoff) of 22.4%, strain differences (engineering versus Green versus Almansi) as large as 14% and elastic modulus differences (Eularian versus Lagrangian) of 44% from ligament tissue sampled from rats. It is therefore critical to maintain consistent (energy conjugate) elastic formulations for reporting mechanical evaluation of soft hydrated tissue.

Algorithms↗
PubMed1988

Calf pump function in patients with healed venous ulcers is not improved by surgery to the communicating veins or by elastic stockings.

Calf muscle pump function was assessed in 41 limbs after venous ulcers had healed. Treatment was then randomized either to ligation of incompetent lower leg communicating veins and ablation of incompetent superficial veins combined with permanent graduated compression elastic stockings, or to graduated compression elastic stockings only. Half volume refilling time (TV1/2) and relative expelled volume (EVrel) measured on foot volume plethysmography were used to assess calf muscle pump function. This was repeated after 12 months. The initial TV1/2 and EVrel were significantly lower than for normal limbs. There was no significant improvement in TV1/2 in either treatment group (Student's t test, P = 0.78, P = 0.19). EVrel did not improve significantly in limbs treated with elastic stockings alone (P = 0.94), but there was a slight but significant improvement in EVrel in limbs treated with surgery and elastic stockings (P = 0.048); however, this was still significantly below the normal range (P less than 0.001). In limbs without phlebographic evidence of post-thrombotic changes, treated with the combination of surgery and elastic stockings, there was a significant improvement in EVrel (P = 0.035), but no improvement was found in limbs with post-thrombotic changes. This small but significant improvement in EVrel in limbs without post-thrombotic changes treated by surgery and elastic stockings may explain the reduced incidence of reulceration that has been found following surgical eradication of the superficial and communicating veins.

Adult↗