Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Isoproterenol treatment leads to endomyocardial fibrosis with muscle fibers encircled by fibrillar collagen. This study was undertaken in the rat to determine if muscle encased in collagen would subsequently become either necrotic or atrophic. For this purpose, we monitored the fibrillar nature of myocardial collagen, its alignment with muscle, and the morphology of the endomyocardium, together with the response in diastolic and systolic myocardial stiffness, immediately on completion (10 days) and 30 days after a course of subcutaneous isoproterenol (500 micrograms/kg/day). We found 1) left ventricular hypertrophy at 10 and 30 days with an increase in collagen volume fraction (p less than 0.01) that consisted of a meshwork of thick and thin collagen fibers that encircled endomyocardial muscle, 2) a variable reduction in endocardial muscle fiber diameter at 30 days with the greatest thinning seen in muscle encircled by fibrous tissue, and 3) an elevation (p less than 0.01) in the slope of the diastolic stress-strain relation at 10 and 30 days. The developed systolic stress-strain relation, which was elevated at 10 days (p less than 0.01), declined (p less than 0.05) with the reduction in endomyocardial muscle mass. Thus, endomyocardial muscle, encircled by fibrillar collagen, will atrophy over time, and this leads to a reduction in active stiffness. These findings may, in part, explain why progressive ventricular dysfunction accompanies chronic myocardial disease with endomyocardial fibrosis.
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PMID:Fibrosis-induced reduction of endomyocardium in the rat after isoproterenol treatment. 252 93

Fetal membranes obtained from second-trimester abortions, elective Caesarean sections and after normal deliveries were studied. The hydrolytic activity against a DNP-peptide expressing the collagen turn-over was found to be very high in the second trimester and relatively high at term of pregnancy. The activity in the chorion was twice that in the amnion. The concentration of another collagen-degrading enzyme, leukocyte elastase, which is present during inflammatory reactions was high at the site of rupture. The collagen concentration given as micrograms hydroxyproline per mg dry weight was unchanged throughout pregnancy and labour in both fetal membranes. The concentration in amnion was twice that in the chorion. After delivery, the collagen content given as microgram/cm2 in the chorion was decreased at the rupture line. This was due to decreased thickness of the membrane, whereas the hydroxyproline concentration (microgram/mg dry weight) was unchanged. The amnion was thinner than the chorion, but the decreasing collagen content (micrograms/cm2) at the rupture line was less pronounced. The thinning of especially the chorionic membrane might be secondary to the mechanical stress of pregnancy and labour and/or, as our results suggest, due to enhanced catabolism.
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PMID:The concentration of collagen and the collagenolytic activity in the amnion and the chorion. 254 Oct 32

Arthroscopic, macroscopic and histological signs of degenerative changes in the articular disc were found in 228 temporo-mandibular joints from corpses. In this way it was possible to identify a degenerative development series. Three preferred sites are typical of degenerative metaplastic processes: antero-lateral in the fibrocartilaginous section, lateral at the transition between fibrocartilaginous and bilaminar section and postero-central in the bilaminar zone. The beginning of a degenerative process was never detected in other sections of the disc. Degeneration commences in the fibrocartilaginous section with fragmentation of the collagen fibres, destruction of interzellular substance and loss of collagen fibres proceeding from the cranial surface. This leads to thinning, rupture and, finally, to dehiscence. In the bilaminar zone the degeneration develops in the caudal section of the cranial lamella. It leads to ganglia formation due to mucoid liquefaction. After tearing of the cranial lamella the caudal lamella thins down until it finally ruptures. Dehiscence thus occurs dorsally, too.
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PMID:[Articular disk degeneration in the TMJ]. 263 76

Despite an overall thinning of the epidermis and focal areas of cytologic atypia, there was no morphologic evidence that the protective function of this tissue was compromised by age. The characteristic morphologic markers associated with the keratinization process were not altered either in appearance or in amounts. A well-formed stratum corneum was present, suggestive that barrier ability is not compromised in senile skin. Whereas alterations in the aged epidermis are slight, the dermal-epidermal changes are marked and have greater physiologic consequences. The major change is a relatively flat dermal-epidermal junction because of retraction of the epidermal papillae as well as the microprojections of basal cells into the dermis. This flattening results in a more fragile tissue that is less resistant to shearing forces. Retraction of the epidermal downgrowths may also explain the loss in proliferative capacity associated with the aged epidermis. The major alterations in the aged dermis concern the architecture of the collagen and elastin networks. Both fibrous components appear more compact because of a decrease in the voids or spaces between the fibers; the spaces resulted from a loss of ground substance. Collagen bundles appear to unravel, and the individual elastic fibers show signs of elastolysis. The net effect of these fibrous rearrangements and alterations is a dermis that is less stretchable, less resilient, more lax, and prone to wrinkling.
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PMID:Morphology of aged skin. 264 2

Clinical tissue expansion has been quite successful but takes 2 to 3 months. This study compares the effects of a conventional tissue expansion regimen of 6 weeks with an accelerated regimen of 2 weeks in the dog model, which is biomechanically similar to the human. In 22 dogs, the skin expanded 34.4 percent in the 2-week and 35.8 percent in the 6-week protocol, excluding stretch and recruitment. There was thinning of the panniculus carnosus in the 6-week group and otherwise no significant decrease in dermal thickness in either group. The biomechanical properties of elasticity and creep did not differ in expanded skin from both groups, while stress/relaxation mildly decreased from a control value of 53.5 percent to 48.8 percent in the 6-week group (p less than 0.05). Collagen activity was increased in both the 6-week and the 2-week groups (p less than 0.001) over nonexpanded skin, and immunohistochemical staining with a monoclonal procollagen antibody demonstrated collagen synthesis by dermal fibroblasts in both groups. We conclude that rapid tissue expansion did not demonstrate any deleterious effects when compared with a conventional regimen.
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PMID:Physical, biomechanical, histologic, and biochemical effects of rapid versus conventional tissue expansion. 292 4

The ultrastructural study of a case of snail track degeneration shows the presence of lipid inclusions in both the glial and the macrophage cells in every layer of the retina, and the existence of intraretinal fibers different from collagen fibers appearing to be glial filaments similar to those found in astrocytic gliomes and to the Rosenthal fibers observed in senile nervous cells. Other features were thinning of the retina and absence of blood vessels in the retina. There are no abnormalities of the vitreo-retinal juncture. All the lesions are in agreement with those observed by Daicker [Ophthalmologica, Basel 165: 360-365, 1972; Klin. Mbl. Augenheilk. 172: 581-583, 1978] with some differences, however. They are different from those found in lattice degeneration. They show that snail track degeneration is a specific form of peripheral retinal degeneration which is quite different from lattice degeneration and must not be considered similar.
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PMID:[Lattice degeneration of the peripheral retina: ultrastructural study]. 299 82

Keratoconus is a bilateral disorder of corneal shape which may be sporadic or genetically determined. Early corneal thinning suggests that a functional loss of structural elements is a primary event in the disease. Tensile strength of the cornea is reduced and is expressed by signs of rupture and scarring in Bowman's layer, scarring in the substantia propria, and rupture of Descemet's membrane. The overall stretching of the cornea results in an increase in curvature while an increased area of the corneal surfaces probably determines the onset and form of Fleischer's ring and the occurrence of endothelial polymegathism. Biochemical studies have shown an increase in collagenolysis and of reduceable collagen cross-links, but there is inconsistent evidence of altered solubility or of hydroxyproline or proteoglycan content. Of recent interest is the characterization of proteoglycan bridges along and between corneal collagen fibrils in keratoconus and the apparent loss of keratan sulphate demonstrated by electron-histochemical and x-ray diffraction techniques. The manner in which this could interfere with corneal strength is discussed.
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PMID:Keratoconus. 304 80

The posterior portion of the Descemet's membrane was studied by scanning and transmission electron microscopy; the materials comprised 87 human peripheral corneas with ages from 2 to 98 years, 5 monkey corneas and 4 rabbit corneas. In some specimens, the endothelium was removed by ultrasonication. After removal of the endothelium, "curly structures" were recognized on the surface of the Descemet's membrane, where the membrane showed a gradual thinning. These structures appeared along the whole circumference of the cornea with variable width in the human specimens, but in monkey and rabbit corneas, the extent of these structures was less than in the human cornea. The "curly structures" were not encountered in young subjects, and they increased with age. There was a positive correlation (r = 0.60, P less than 0.001) between the age and the extent of these structures. Other aging products of the Descemet's membrane, ie, Hassall-Henle bodies, were partly surrounded by the "curly structures". The human "curly structures" consisted of collagen fibrils, halo structures in the collagen bundles, wide-spacing fibers, microfibrils, ground substances containing minute filaments and a structure resembling the Descemet's membrane. Components of "curly structures" of the monkey and rabbit were almost the same as those of the human except for the Descemet's membrane-like structure.
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PMID:Electron microscopic observations of Descemet's membrane of peripheral cornea. 308 4

Pectus excavatum is a common malformation in diseases of elastic tissue (Marfan, Ehlers-Danlos...). When observed apparently alone it may represent a minor form of dystrophy, implying the same risk of a cardiac lesion. Abnormalities of the thoracic skeleton and echocardiographic mitral valve prolapse is a well established association, suggesting a common disorder of connective tissue. However, there is no absolute proof that this is a statistically significant association. Histological connective tissue changes relating these two markers have yet to be found. Clinical and echocardiographic examinations and skin biopsies were performed in 17 patients with pectus excavatum. Mitral valve prolapse was detected in 65% of cases (associated in 1 out of 3 cases with tricuspid valve prolapse). In 53% of cases electron microscopy showed abnormal skin collagen and elastin. Collagen abnormalities were twice as common as those of elastin and could be associated. Mixed changes of thinning of elastin and collagen fibres of irregular calibre were particularly suggestive. Pectus excavatum would therefore seem to be the expression of a minor form of dystrophy of collagen and elastin tissues and a clinical marker of possible mitral valve prolapse.
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PMID:[Mitral valve prolapse and pectus excavatum. Expressions of connective tissue dystrophy?]. 309 Sep 60

To evaluate the dermal and epidermal response to soft-tissue expansion in the pig, round tissue expanders were placed dorsally under tattooed patterns and inflated over 6 weeks. Surface area, skin thickness, histologic changes, and collagen content were evaluated at 6-week intervals. Epidermal thickening and dermal thinning were observed. Dermal thinning persisted 36 weeks after expansion. Dermal collagen content was decreased, although collagen density remained unchanged. Total collagen content calculated within an expanded square grid increased. These data support a theoretical gain in the dermal layer as well as epidermal layer in response to tissue expansion.
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PMID:Dermal and epidermal response to soft-tissue expansion in the pig. 334 Jun 74


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