Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.4.3.13 (lysyl oxidase)
 1,248 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.
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PMID:Early changes in the arterial wall of chickens fed a cholesterol diet. 0 48

Lysyl oxidase catalyzes the crosslinking of collagen and elastin. Lysyl oxidase activity was measured and localized in rat liver during the evolution of hepatic fibrosis induced by CCl4. Enzyme activity measured with DL-[6-3H]-lysine-labeled collagen substrates in liver and plasma increased sharply after approximately 3 wk of injection, reached a maximum at 6 wk, and then decreased. The increase in activity correlated histologically with early connective tissue septa formation, and the magnitude of increase was significantly greater than that found for the intracellular collagen biosynthetic enzymes protocollagen prolyl hydroxylase and lysyl hydroxylase. Indirect immunofluorescence studies showed that lysyl oxidase was present in association with collagen in the extracellular space. However, it was not possible to correlate the distribution pattern with a particular liver cell type. These observations suggest that serial measurements of lysyl oxidase activity in liver or plasma may be useful for correlating changes in connective tissue formation with histologic connective tissue deposition.
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PMID:Biochemical and immunochemical study of lysyl oxidase in experimental hepatic fibrosis in the rat. 2 18

Lysyl oxidase was partially purified from serum by a diethylaminoethyl batch procedure in the presence of 6 mol/L urea and dialyzed against 3 mol/L KSCN. Using this method, we determined serum lysyl oxidase activity in 52 patients with liver disease and in 14 healthy controls, and we examined usefulness of serum lysyl oxidase in assessing liver fibrogenesis. For this purpose, serum lysyl oxidase activity in chronic liver disease was compared with serum levels of prolyl hydroxylase and laminin P1. As compared with controls, serum lysyl oxidase activity increased 1.6-fold in chronic persistent hepatitis, 4.4-fold in chronic active hepatitis and 11.8-fold in cirrhosis, indicating an increase in concert with the development of liver fibrosis. In hepatocellular carcinoma, the serum activity, although significantly increased, was lower than that in cirrhosis. Serum prolyl hydroxylase was significantly increased in chronic active hepatitis, in liver cirrhosis and in hepatocellular carcinoma. Serum laminin P1 was significantly increased in chronic active hepatitis, in cirrhosis and in hepatocellular carcinoma. Serum lysyl oxidase activity did not correlate significantly with serum levels of prolyl hydroxylase and laminin P1 in any subject or in any subgroup. The magnitude of the increase and the abnormal percentage of serum lysyl oxidase activity were larger than those for serum prolyl hydroxylase and laminin P1. These results suggest that serum lysyl oxidase activity is a more sensitive indicator of liver fibrosis than serum prolyl hydroxylase and laminin P1.
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PMID:Serum lysyl oxidase activity in chronic liver disease in comparison with serum levels of prolyl hydroxylase and laminin. 168 40

The levels of two enzymes of collagen biosynthesis namely lysyl oxidase and prolyl hydroxylase were measured in the lungs of rats 3 and 6 weeks after receiving a single intratracheal instillation of silica or sterile saline. Circulating levels of lysyl oxidase were also estimated. Significant increased lung-enzyme activities were observed in the silica-exposed rats at both time intervals. Plasma levels of lysyl oxidase were also found to be raised in the silica-exposed rats. These changes were not, however, accompanied by profound pathological alterations. These results demonstrate that after exposure to silica histologically detectable fibrosis is preceded by significant changes in the activities of enzymes associated with collagen synthesis.
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PMID:Measurements of enzymes of collagen synthesis in rats with experimental silicosis. 285 71

The activities of prolyl 4-hydroxylase, galactosylhydroxylysyl glucosyltransferase (GGT) and lysyl oxidase (three enzymes catalysing post-translational modifications of collagen) were measured in the lungs of rats exposed to silica (DQ12). Circulatory levels of GGT were also estimated. Rats were killed after 24 h and at 6, 12 and 24 weeks after a single intratracheal instillation of either 12.5 or 25 mg of silica (DQ12). Control animals received saline. The total activity of the three enzymes in the lungs of the exposed animals was significantly increased at all times (P less than 0.05). The circulatory levels of GGT were also increased though some differences failed to reach significance. Thus increased activities of enzymes of collagen biosynthesis correlated with the development of silicosis and occurred within 24 h of treatment. This suggests that the changes responsible for the eventual development of fibrosis are operative within hours of dust exposure.
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PMID:Collagen biosynthesis enzymes in lung tissue and serum of rats with experimental silicosis. 286 66

Streptozotocin (STZ)-induced diabetes (8 weeks) produced a marked depressor effect in the spontaneously hypertensive rat (SHR), confirming earlier studies, but had no effect on arterial pressure of normotensive controls (WKY). We investigated the phenomenon further by examining the effects of diabetes on the activities of aortic prolyl hydroxylase (PH) and lysyl oxidase (LO), marker enzymes for collagen biosynthesis, and on the reactivity of isolated mesenteric arteries to vasoactive agents. PH and LO activities of nondiabetic SHR were greater than those of the WKY controls. Diabetes markedly reduced PH and LO activities of SHR aortae, but had no significant effect on PH and LO activities of the WKY strain. The effects of diabetes on vascular collagen biosynthetic enzymes of SHR were not associated with reductions in mesenteric arterial responsiveness or sensitivity to norepinephrine, methoxamine, serotonin or KC1. These results suggest that the depressor effect of diabetes in SHR is associated with a reduction in vascular collagen biosynthesis but not a reduction in vascular reactivity.
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PMID:Depressor effect of diabetes in spontaneously hypertensive rat: role of vascular reactivity and prolyl hydroxylase and lysyl oxidase activities. 286 37

Collagen fibers in the ovarian follicle undergo drastic changes at ovulation due to the preovulatory increase of collagenolytic activities. The collagen synthesis in ovaries, however, has not been elucidated yet. To clarify the regulatory role of prostaglandins (PGs) in collagen synthesis of the follicular wall in relation to the ovulatory process, we measured prolyl hydroxylase (PH), as well as lysyl oxidase (LO) activity and the content of hydroxyproline (Hyp) in ovarian follicles of the rabbits treated by hCG, hCG/indomethacin (IM) and hCG/IM/various PGs. The experimental groups consisted of; 1) untreat control group 2) ovulatory group receiving hCG 3) non-ovulatory group given PGs 4) ovulatory group given hCG and PGs 5) group in which hCG-induced ovulation was inhibited by IM (4 mg/kg) 6) group in which IM-inhibited ovulation was recovered by PGF2 alpha (1.5 mg/kg) 7) group in which IM-inhibited ovulation was not restored by PGE1 (0.1 mg/kg) and PGE2 (0.7 mg/kg). The peak activities of PH and LO in ovarian follicles were observed at 12-13 hr after hCG injection, namely, immediately after ovulation. Significant changes of these activities after hCG administration were specific to the ovaries. PH activity in the ovaries was suppressed by the administration of IM, but LO activity was not significantly suppressed. In the hCG/IM/PGF2 alpha-treated ovulatory rabbits (Group 6), PH activity recovered to nearly the level of the hCG-treated rabbits (Group 2). By addition of PGE2, ovulation did not recover but PH activity was restored to about 70% of the hCG-treated rabbits. PGE1 did not have any effect on the reversal of ovulation-blockage or restoration of PH activity. The amount of Hyp after hCG administration tended to decrease from 6 hr to 10 hr but was significantly increased from 10 hr to 13 hr. This increase of Hyp after ovulation significantly correlated with the increase of PH and LO activities. In the hCG/IM/PGF2 alpha-treated rabbits (Group 6), the changes of Hyp were similar to those the hCG-treated rabbits (Group 2). In conclusion, collagen synthetic activity, found to be regulated by PH and LO activities in the ovarian follicles, was activated after follicle rupture, resulting in reconstruction of collagen fibers, and PGs play an important role in the ovulatory process by modifying collagen synthesis.
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PMID:[Effect of prostaglandins on collagen synthesis in rabbit ovarian follicles during the ovulatory process]. 287 49

This study assessed the responses of lysyl oxidase, the enzyme that initiates covalent crosslinking in elastic and collagen, by studying the aortic tissue of rabbits after arteriosclerosis had been induced by diet. Rabbits in the experimental group were fed an atherogenic diet of rabbit chow supplemented with 8% peanut oil and 2% cholesterol for varying periods of time, while the control group was fed only rabbit chow. Lysyl oxidase activity was found to be distributed throughout the length of the thoracic and abdominal aortas of the normal rabbits, However, rabbits fed the atherogenic diet showed marked increases in enzyme in the aortic arch, a change that was initially evident after 30 days and became greatest (2.5 times that of the controls) after 90 days. Enzyme activity in the study rabbits increased only minimally in the abdominal aortic wall. Aortic prolyl hydroxylase activity measured after 60 days of feeding changed in degree and manner similar to lysyl oxidase activity. These region-specific changes in enzyme activities correlated with the distribution and severity of aortic lesions in this model of the disease. Lysyl oxidase activity increased dramatically in this model of atherosclerosis, suggesting that this extracellular enzyme activity may prove to be a vulnerable and accessible point of control of the fibrotic response in atherosclerosis.
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PMID:Changes in aortic lysyl oxidase activity in diet-induced atherosclerosis in the rabbit. 611 70

Industrial workers who are accidentally exposed to cadmium fumes often develop severe lung damage leading to widespread peribronchiolar scarring. This study examined the effect of a single exposure of cadmium chloride aerosol on rat lung lysyl oxidase and prolyl hydroxylase, both markers of connective tissue biosynthesis. Rats were killed at 2, 4, 7, 10, and 21 days after a 2-h exposure to 0.1% Cdcl2 aerosol. Total lung lysyl oxidase was increased 14.8 times that a saline control animals by 4 days and returned to near normal values by 10 days. Interestingly, a small amount of lysyl oxidase activity was also detectable in the lung lavage of unexposed animals and was markedly elevated at the earlier times after cadmium exposure. Total lung prolyl hydroxylase activity paralleled that of lung lysyl oxidase and increased 7.4-fold by the fourth day. A significant increase in total lung hydroxyproline could be demonstrated. Administration of beta-aminopropionitrile, an irreversible inhibitor of lysyl oxidase, prevented much of the increase in lysyl oxidase activity and the accumulation of collagen. The altered tissue amounts of lysyl oxidase and prolyl hydroxylase after cadmium inhalation correlated well with the marked interstitial cell hyperplasia 4 to 5 days after exposure and suggested that connective tissue protein synthesis is activated in the interstitial cell fibroblasts soon after cadmium exposure.
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PMID:Lung lysyl oxidase and prolyl hydroxylase: increases induced by cadmium chloride inhalation and the effect of beta-aminopropionitrile in rats. 611 50

Lysyl oxidase and collagenase activities were measured in experimental acute and chronic liver injury in mice and rats, and correlated with collagen synthesis and accumulation. Acute liver injury was induced in mice and rats by a single dose of carbon tetrachloride given by gavage, and also in mice by a single injection of murine hepatitis virus. Chronic liver injury was induced in rats by repeated injections of carbon tetrachloride. Elevated plasma glutamic oxaloacetic transaminase levels, increased hepatic prolyl hydroxylase activity, and increased synthesis of collagen-bound hepatic hydroxyproline occurred in animals with acute as well as with chronic liver injury. However, only chronic liver injury appeared to be associated with fibrosis, increased collagen-bound hydroxyproline content, increased hepatic lysyl oxidase and collagenase activities, as well as with increased serum lysyl oxidase activity. These data suggest that lysyl oxidase and collagenase may play an important role in the collagen accumulation associated with hepatic fibrosis.
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PMID:Lysyl oxidase and collagenase in experimental acute and chronic liver injury. 611 72


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