Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: HUMANGGP:031673 (collagen)
 124,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A total of 160 1-2 day old chickens were fed a 2% cholesterol diet for a period of 8 to 42 days and compared with an equal number of controls. Aortas were analyzed for various indexes of reactivity of connective tissue, cholesterol content and scanning electron microscopy (SEM) characteristics of the endothelial lining. Cholesterol feeding for a period up to 6 weeks resulted in doubling the level of serum cholesterol. It was, however, without effect on the activity of prolyl hydroxylase, lysyl oxidase, collagenase and collagen content in the aortic wall. As early as 3 weeks of feeding significant changes occurred in total and esterified cholesterol content. At the same time endothelial cells were characteristically contracted with several long cytoplasmic elongations and protrusions. A significant decrease of activity of the above enzymes was found in aortic tissue with increased age of the chicken. Collagen content in aortas increased with age of chickens. It is concluded that cholesterol as an atherogenic agent induces marked changes in endothelial cells and lipids of chicken aorta at earlier periods, prior to the activation of connective tissue.
Atherosclerosis 1976 Sep
PMID:Early changes in the arterial wall of chickens fed a cholesterol diet. 0 48

Using the histological staining methods of Weigert and of Masson on primary cultures of rat aortic media cells, we obtained additional proofs of the smooth muscle cell's ability to secrete collagen and elastin in vitro: the percentage of positive flasks with aorta rings was the same throughout the follow-up, but increased gradually for the new tissue growing around the rings.
Atherosclerosis 1976 Oct
PMID:Histological arguments for collagen and elastin synthesis by primary cultures of rat aortic media cells. 6 79

Lysyl oxidase is the copper-dependent enzyme responsible for the normal cross-linking of both collagen and elastin which is necessary for their functional integrity. There is now strong evidence that this enzyme is vitamin-B6-dependent. The earliest visible lesion of atherosclerosis, commonly found in human neonatal coronary arteries and probably indicative of the location of future atherosclerotic plaques, is a focal splitting of the internal elastic lamina, the cause of which has hitherto remained unexplained. It is suggested that this lesion is the result of imperfect cross-linking of arterial elastin as well as collagen, and is caused by a maternal deficiency of vitamin B6 which is commonly found in pregnancy and which could thus impair the function of lysyl oxidase. Prophylactic supplementation of maternal diet with adequate vitamin B6 is therefore suggested.
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PMID:The aetiological role of maternal vitamin-B6 deficiency in the development of atherosclerosis. 6 31

A number of soluble proteins contained in human aortic intimal tissue was extracted into buffered saline (pH 7.4) and identified and quantitated by immunoelectrophoresis and immunodiffusion. The proteins included IgA, IgG, IgM, B1C (C3), alpha 1-antitrypsin, alpha 2-macroglobulin, fibrinogen, albumin, LDL, HDL, alpha 1-acid glycoprotein, beta 2-glycoprotein, transferrin and ceruloplasmin. The concentration of soluble proteins was significantly higher in the atherosclerotic intima than in the normal intima. The diseased intima also contained a small amount of tissue-bound IgG, IgA and B1C which was extractable with citrate buffer at pH 3.2. The vascular band IgG, and B1C were shown by enzymatic and immunohistochemical studies to be closely associated with the collagenous tissue of the plaque. The Ig contained in the atherosclerotic plaque may be derived in part from the biosynthesis of Ig by the artery, since the incorporation of 14C-labeled leucine into IgG by the atheromatous plaque was demonstrable by radioimmunoelectrophoresis. In contrast to the diseased artery, the normal artery did not synthesize IgG and did not contain vascular bound IgG or complement. However, the normal artery was capable of fixing IgG and B1C eluted from the diseased artery. The present studies suggested that the IgG contained and synthesized by the plaque might represent an immune response to an endogenous or exogenous antigen closely associated with plaque collagen. IgG and B1C either alone or in the form of an immune complex also may play an important role in phagocytosis in the plaque and thereby influence the course of atherosclerosis. The proteolytic inhibitors, alpha 1-antitrypsin and alpha 2-macroglobulin, found in relatively high concentrations in the plaque, could enhance fibrosis of the lesion because of thier known inhibitory effects on collagenase and elastase.
Atherosclerosis 1979 Dec
PMID:Soluble proteins in the human atherosclerotic plaque. With spectral reference to immunoglobulins, C3-complement component, alpha 1-antitrypsin and alpha 2-macroglobulin. 9 93

Aortic pulse wave velocity was determined in Macaca fascicularis monkeys fed either atherogenic or control diets for 36 months. The foot-to-foot velocity and apparent phase velocities of the second through seventh Fourier harmonics at a given diastolic pressure in the atherosclerotic monkeys were 1.5 to 2.0 times the values for the control animals. More than 80% of the aortic intimal surface of the atherosclerotic monkeys was covered with fibrous or fatty plaque, which approximately doubled wall thickness and wall thickness to radius ratio. Angiochemical evaluations showed no difference in collagen or elastin concentration (as a fraction of lipid and mineral-free dried aorta), but the atherosclerotic aortas were 1.5 to 2.0 times that of control in collagen and elastin content (defined as the absolute quantity beneath a square centimeter of intimal surface). Total cholesterol and calcium concentrations in the atherosclerotic aortas were more than 10 times the values for the control aortas. The static circumferential distensibility of the excised atherosclerotic aortas was significantly less than control, but there was no difference in incremental (Young's) modulus of elasticity. The in vitro pressure-strain elastic modulus of the atherosclerotic aortas was more than twice that of control, which was predicted from the enhanced wave velocity. The significantly increased stiffness of the atherosclerotic arteries appeared to be due mainly to the increased wall thickness caused by the atherosclerotic plaques rather than to material changes described by Young's modulus. Extensive medial damage, however, also was present and could have had a major influence on stiffness. Atherosclerosis therefore can result in increased aortic stiffening, detectable by pulse wave velocity, even if there is no change in the overall Young's modulus of elasticity.
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PMID:Aortic pulse wave velocity, elasticity, and composition in a nonhuman primate model of atherosclerosis. 9 6

The effects of the anticalcifying drug, ethane-hydroxydiphosphonate (EHDP) and the inhibitors of collagen biosynthesis, colchicine, penicillamine and azetidine were studied in the rabbit with pre-established atherosclerosis. The drugs were administered with a cholesterol-free diet (regression diet) for 8 weeks following the induction of atherosclerosis by feeding a hypercholesterolemic diet containing 2% cholesterol and 8% peanut oil for 8 weeks. The extent and severity of aortic atherosclerosis, as revealed by the morphological and biochemical findings, increased significantly during the regression period. In rabbits treated with EHDP (5 mg/kg/day) the aorta had fewer gross lesions and contained significantly less cholesterol, collagen and elastin than did the aorta of the rabbits fed the regression diet alone. These changes were associated with a significant reduction in aortic calcium caused by EHDP. The aortic content of cholesterol, collagen and elastin in the EHDP-treated rabbits, although less than that of the rabbits fed the regression diet alone, was about the same as that of the rabbits fed a high cholesterol diet for 8 weeks. Both colchicine (0.2 mg/kg/day) and penicillamine (100 mg/kg/day) had a selective action on the induced plaques in that they suppressed the fibrous proliferation in the lesions without preventing lipid and calcium accumulation in the lesions. Neither colchicine nor penicillamine reduced the extent of aortic atherosclerosis as determined by gross examination of the vessel. Azetidine had no significant effect on the pre-established atherosclerotic lesions. The lipid, fibrous protein and calcium content of the aorta of the azetidine-treated animals was not significantly different from that of the untreated animals. The biochemical findings in the aorta were consistent with the microscopic changes.
Atherosclerosis 1979 May
PMID:Effects of anticalcifying and antifibrobrotic drugs on pre-established atherosclerosis in the rabbit. 11 83

We have demonstrated that in rhesus monkeys, 18 months of diabetes alters the end-diastolic pressure, end-diastolic volume relations without hypertrophy. Accumulation of collagen in the myocardial interstitium was the apparent basis for abnormal left ventricular performance. Neither collagen concentration nor left ventricular performance were signigicantly affected by dietary lipid composition. These myocardial abnormalities occurred at a stage when coronary atherosclerosis was limited. However, the relative influence of coronary atherosclerosis and myocardial alterations during more prolonged lipid feeding remains to be determined.
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PMID:Altered myocardial function and collagen in diabetic rhesus monkeys on atherogenic diet. 11 54

Platelet adhesion to the subendothelium of the vessel wall and to its collagen component plays a key role in hemostasis, thrombosis, and the development of atherosclerosis. In order to study the mechanisms of platelet adhesion and eventually to inhibit adhesion, it has been necessary to develop methods that measure platelet adhesion quantitatively in vivo and in vitro. In this article, the methods that are used to measure platelet adhesion are reviewed critically with emphasis on their aims, advantages, and disadvantages. The methods that are used to measure platelet adhesion can be divided in five groups: (1) methods that use an aggregometer to measure platelet adhesion to collagen in the presence of EDTA; (2) methods that use binding of radiolabeled collagen, affinity chromatography, or gel filtration; (3) the morphometric method of Baumgartner that measures platelet interaction with the subendothelium of an aorta exposed to flow in an annular perfusion chamber; (4) the quantitative isotopic measurement of platelet adhesion to collagen-coated surfaces and to subendothelium with the rotating probe device of Cazenave; and (5) in vivo platelet adhesion to the subendothelium measured by the morphometric method or with platelets radiolabeled with 51Cr or 111In. With these methods is has been possible to study the factors (Ca2+; VIII: von Willebrand factor; hemodynamic factors: red cells, shear rate; components of the vessel wall) governing platelet adhesion to subendothelium and to collagen. It has also been possible to screen and study drugs inhibiting platelet adhesion, which is the first step in the formation of a thrombus at the site of vascular injury.
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PMID:[In vivo and in vitro methods of studying platelet adhesion to the components of the vascular wall]. 12 39

Auto-alloplastic arterial prostheses with a dacron mesh of 1 or 2 layers according to Sparks were investigated by light and electron microscopy after variable times of incorporation and perfusion. At the end of the organization-period the characteristic structure of the wall is composed of three layers. The interior layer is adapted to the form of the mandril, which holds the place of the lumen, the medial layer is formed according to the inforcing dacron-mesh. With increasing duration of incorporation the granulation tissue shows somewhat less inflammatory cells and capillaries and more collagen fibres. There were some characteristic disturbances of healing only partly due to infection, which resulted in focal or total necrosis of the granulation tissue: Not all of these findings were of clinical importance. Already after a perfusion time of 10 months an atherosclerosis of variable degree was found. This atherosclerosis started from mural thrombi and showed in the electron microscope proliferations of modified smooth muscle cells. Advantages and disadvantages of the autoalloplastic arterial prostheses are discussed.
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PMID:[Light- and electronmicroscopic findings in nine auto-alloplastic vascular grafts (Sparks-Mandril) (author's transl)]. 12 63

Male albino rabbits were exposed to intermittent nitrogen breathing every 30 sec for 5 sec, 15 min daily over a period of 3 weeks, and every 30 sec for 5 sec over a period of 10 hr. A third group of animals was exposed continuously to 8% oxygen breathing for 2 weeks. Neither intermittent not continuous hypoxia induced gross or microscopic alteration in the aorta. The effects of hypoxia upg which hypoxia was distributed than upon the total period or the degree of hypoxia. Exposure to hypoxia over a short period stimulated the synthesis of glycosaminoglycans, whereas distribution of the hypoxia over a longer period resulted in a reduction in the amount of glycosaminoglycans, probably secondary to an inhibition of the synthesis. Similarly, continuous exposure to 8% oxygen for a longer period decreased the aortic content of collagen. The alterations in the glycosaminoglycans and collagen induced by hypoxia may cause changes in the passage of macromolecules through the aortic wall. The changes may also influence the mechanical properties of the aorta and lead to impaired healing of vascular injury.
Atherosclerosis
PMID:Effects of intermittent and continuous hypoxia on the aortic wall in rabbits. 12 91


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