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)

An acute myocardial infarction, particularly one that is large and transmural, can produce expansion and alterations in the topography of both the infarcted and non-infarcted regions or the ventricle. This remodelling can importantly affect the function of the ventricle and the prognosis. Side-to-side slippage of myocytes in the myocardium occurring in association with ventricular dilatation is responsible for wall thinning. The increased internal load that is sustained through the cardiac cycle is thought to promote further stress, dilatation and hypertrophy of the non-infarcted area. The collagen network has been showed to be high responsible for the remodelling of the interstitium and therefore for the scar formation involved in the expansion. The process for ventricular enlargement can be influenced by infarct size, healing end ventricular wall stresses. The process of scarification can be interfered with during the acute infarct period by the administration of glucorticosteroids and non-steroidal anti-inflammatory agents, which results in thinner infarct and further expansion. A most effective way to prevent or minimize the increase in ventricular size is to limit the initial insult. Acute thrombolytic reperfusion therapy may work in this way. Finally early and long-term therapy with an angiotensin converting enzyme inhibitor can favorably alter the loading conditions of the left ventricle, reducing progressive enlargement with a prolongation in survival.
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PMID:[Left ventricular remodelling]. 184

The changes induced by ageing of the skin are particularly visible in photo-exposed areas, indicating the interaction between actinic factors and factors specific to the ageing process itself. The corresponding histological signs affect various structures: epidermis (thinning of the epidermis, reduced cell proliferation...), dermis-epidermis junction (disappearance of the microvilli with defective adhesion of the epidermis to the dermis), dermis (degeneration of elastin and collagen, which is photoinduced, and a moth-eaten appearance with loss of microfibrils as a result of time-related ageing), microcirculation (reduced vascularization, particularly visible in photo-exposed areas...) appendages.
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PMID:[Histologic signs of cutaneous aging]. 189 70

Keratoconus, a bilateral corneal disease, is characterized by modifications in corneal shape and thinning of the stroma. From a biochemical point of view, a decrease in collagen content, probably due to the high collagenase activity, has been reported. Gamma Interferon (gamma-IFN), Tumor Necrosis Factor (TNF), and Interleukin 1 (IL1) are peptide regulatory factors involved in immunological responses, but they also play a role in the synthesis of collagen and prostaglandin E2 by fibroblasts. In these experiments, we have determined the number of membrane binding sites for gamma-IFN, TNF, and IL1, and the dissociation constant (Kd) for each radiolabelled ligand. All experiments were carried out on cultured corneal stromal cells. Data from normal human corneas and from keratoconus were compared. No differences were found concerning gamma-IFN and TNF binding sites between normal corneas and keratoconus, while fibroblasts from keratoconus proved to bear four fold more IL1 binding sites than normal fibroblasts, with similar Kd.
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PMID:Binding sites for human interleukin 1 alpha, gamma interferon and tumor necrosis factor on cultured fibroblasts of normal cornea and keratoconus. 191 96

Verapamil, a calcium channel blocker has been used with partial success in cases of primary pulmonary hypertension, as well as to reduce hypoxia-induced pulmonary hypertension (PH) in rats. However, its effect on monocrotaline (MCT)-induced PH in rats is not known. We studied the effect of verapamil on MCT-induced PH. Three weeks after a single injection of MCT, significant PH was noted in the MCT-injected rats compared with control (44.35 +/- 3.5 vs. 22 +/- 2.5 mmHg). MCT-injected rats on daily verapamil showed significant reduction in PH (31.5 +/- 3.4 mmHg). The main pulmonary artery of MCT-injected rats revealed subendothelial thickening, thinning and fragmentation of elastic laminae, smooth muscle cell hypertrophy and necrosis or loss of smooth muscle cells, and increased amounts of collagen in media and adventitia. In contrast, the main pulmonary artery of MCT + VP-treated rats showed less intimal thickening, some smooth muscle cell hypertrophy, but little necrosis or loss of cells in addition to disappearance of outer elastic laminae. Smaller pulmonary arteries (less than 150 microns in diameter) in MCT + VP-treated rats showed less medial thickening than MCT groups. However, diminished lung angiotensin-converting enzyme activity suggestive of endothelial cell dysfunction was noted in both MCT and MCT + VP-treated rats. This study indicates that verapamil attenuates MCT-induced PH, but has no effect on pulmonary endothelial cell dysfunction.
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PMID:Effect of verapamil on monocrotaline-induced pulmonary artery hypertension and endothelial cell dysfunction in rats. 196 10

Growth plate cartilage from normal and vitamin D-phosphate deficient (-VDP) rats was cultured to study the production of collagenase and tissue inhibitor of metalloproteinases (TIMP) in vitro. All tissues secreted latent collagenase into the medium at a constant rate during the 5 days in culture. Microdissected-VDP growth plates, containing predominatly hypertrophic cells, released up to 8-fold more collagenase into the medium than either intact-VDP or normal growth plates. TIMP was also secreted during the culture, but its rate of production was not as dependent on tissue type as collagenase. The tissue level of collagenase and TIMP before culture was compared with that found in conditioned medium and remnant tissue after culture. During the 5 day culture period microdissected-VDP growth plates, containing predominatly hypertrophic cells, produced 3-times more collagenase/microgram DNA over the starting level than either intact-VDP or normal growth plates. TIMP was never found in tissues after they had been cultured, but was present in all tissues before culture except those containing predominatly hypertrophic cells. The amount of TIMP required to block collagenase was calculated. Growth plates in culture produced enough TIMP to block all collagenase found in the medium and remnant tissue, while extracts of uncultured intact -VDP growth plates, and those divided to contain hypertrophic cells, had an excess of collagenase over TIMP. The results suggest that hypertrophic cells produce far more collagenase than other cells in the growth plate, but all cell types have about the same capacity to synthesize TIMP. As a result, increased collagenase synthesis by hypertrophic cells may surpass increases in TIMP synthesis and lead to collagen removal. This would allow for thinning of the longitudinal septa and expansion of the hypertrophic cells.
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PMID:Production of collagenase and tissue inhibitor of metalloproteinases (TIMP) by rat growth plates in culture. 196 14

The myocardium is a complex three-dimensional structure consisting of myocytes interconnected by a dense collagen weave that courses in different directions. Regional ischemia can be expected to produce complex changes in ventricular deformation. In the present study, we examined the effects of ischemia on two- and three-dimensional finite strains during acute transmural myocardial ischemia in 13 open-chest anesthetized dogs. In contrast to systolic deformation observed during the control period in which circumferential shortening exceeded longitudinal shortening, our results indicate that after 5 minutes of acute ischemia, end-systolic in-plane lengthening across the left ventricular wall occurs in approximately equal amounts in the circumferential and longitudinal directions. Along with these changes in extensional strains, there were significant negative transverse shearing deformations during ischemia. Myocardial ischemia also resulted in a loss of the normal end-systolic transmural gradients of shortening and thickening. Three-dimensional end-diastolic strains indicate that the left ventricular wall undergoes a significant passive reconfiguration that varies transmurally with lengthening in the epicardial tangent plane and wall thinning increasing from the epicardium toward the endocardium. The large systolic changes in shearing deformations with ischemia could potentially influence collateral blood flow and certainly indicate that uniaxial measurements of deformation in the ischemic myocardium, which do not account for shearing deformation, are incomplete and must be interpreted with caution. Moreover, normal transmural systolic gradients in deformation, which would be anticipated on geometric grounds, are lost during ischemia, implying that the material properties of ischemic tissue or the loading conditions imposed on the ischemic region by partially impaired adjacent myocardium vary transmurally.
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PMID:Transmural myocardial deformation in the ischemic canine left ventricle. 199 44

An experimental morphological study on the reconstruction of the digital annular pulleys has been carried out in dogs. The segment corresponding to zones 1 and 2 of the flexor apparatus of the 2nd and 5th digits of the left forepaw was chosen for the experiment. The whole flexor apparatus was resected and a single digital pulley (A 2) was reconstructed, using segments of the animals own deep flexor tendon. A length of silicone rubber tube was used as tendon spacer. The new pulleys showed marked degeneration of the collagen fibres and thinning which increased with time and may be the cause of decrease in strength. A layer of mesothelial cells with secretory properties developed at the interface between the tendon graft and the spacer.
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PMID:The fate of tendon grafts used to reconstruct the digital annular pulleys. 200 12

Subjects with chronic alcoholism are associated with a higher prevalence of bone fractures, compared with age-matched controls. However, the pathogenesis of alcoholic osteopathy remains poorly understood. In this study, the bone cells activities and the bone matrix were studied using different techniques such as bone morphometry, scanning electron microscopy and computer reconstruction. Male patients (N = 20), aged 59.1 +/- 10.1 years, presenting a chronic decompensated alcoholic cirrhosis, were admitted into this study. A histomorphometric analysis of a transiliac bone biopsy was done after a double tetracycline labeling of the bone. A scanning electron microscopy (SEM) study was performed on eight out of the 20 patients on an additional biopsy. The bone mass was significantly decreased in cirrhotic patients. A marked defect in the osteoblastic function was observed with reduced osteoid parameters, lower mean wall thickness, and slower bone formation rate leading to a thinning of bone trabeculae. Conversely, trabecular resorption surfaces were markedly increased. SEM examination of bone biopsies was also consistent with delayed and impaired osteoblastic activity leading to extended and scalloped resorption surfaces covered by unusually thin layers of calcified collagen fibers. The reduced osteoblastic activity associated with normal osteoclastic function appears to play a major role in the pathogenesis of alcoholic osteoporosis leading to decreased bone mass with thinner trabeculae.
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PMID:Alcoholic cirrhosis and osteoporosis in men: a light and scanning electron microscopy study. 204 77

In order to identify the direct pathogenic factors involved in the stromal thinning of keratoconus, quantitative analysis of keratocytes, collagen fibers and collagen lamellae in keratoconus cornea was performed histologically by light and electron microscopy. Both normal and keratoconus corneas showed a similar cell density of keratocytes in the central stroma, therefore the total number of keratocytes in keratoconus cornea might be smaller than that of controls, because of the thinning of stroma in the keratoconus. The collagen lamellae in keratoconus corneas showed a significant decrease in number compared with controls. There was a direct relationship between the stromal thickness and number of collagen lamellae. On the other hand, there was no statistical significance between normal and keratoconus corneas in terms of the thickness of collagen lamellae. These results suggest that the thinning of the cornea in keratoconus might occur as the result of a defect of some collagen lamellae due to a disorganization during the process of collagen lamellae formation.
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PMID:[Quantitative analysis of collagen fiber in keratoconus]. 207 70

When deprived of form vision during postnatal development, tree shrews reliably develop an axial myopia characterized by elongation of the vitreous chamber, zonular dysplasia and a slight reduction in lens weight and thickness. Corneal flattening has been observed in animals visually deprived by eyelid suture but is absent in animals visually deprived with an opaque goggle. The sensitive period for myopia development starts about 15 days after the eyes open and sensitivity remains high for about 3-4 weeks thereafter. Recovery from experimental myopia can occur in tree shrews that are visually deprived using goggles for a short period. Blockade of action potentials from ganglion cells in deprived eyes by intravitreal injections of tetrodotoxin (TTX) does not prevent the development of myopia, suggesting that local retinoscleral mechanisms can contribute to experimental myopia in this species. Open eyes receiving intravitreal injections of either saline or TTX have shorter vitreous chambers than control eyes, suggesting that puncturing the globe reduces forces within the eye that contribute to its expansion. Animals treated intraperitoneally with lathyritic agents to block collagen cross-linking for three weeks during a 75-day period of monocular visual deprivation develop a very large myopia in the visually deprived eye that is accompanied by a large vitreous chamber elongation and marked thinning of the posterior sclera. The results from studies in tree shrews are consistent with the suggestion that an internally driven expansion acts in concert with ocular growth to increase the axial length of the eye, helping to move the eye from hyperopia toward emmetropia. The resistance of the sclera and/or choroid to this expansion may be affected by activity within the retina. Increased retinal activity associated with achieving a clear image on the retina may result in increased resistance to expansion, helping to hold the retina at the focal plane. Recovery may occur by a slowing of axial expansion while the optical surfaces proceed toward adult values.
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PMID:Experimental myopia in tree shrews. 208 76


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