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Query: HUMANGGP:031673 (collagen)
 124,196 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of local hyperalimentation on developing granulation tissue was studied in rats. Cylindrical hollow viscose cellulose sponge implants were used subcutaneously as an inductive matrix fro the growth of granulation tissue. In the first, control group the implants were kept untouched while the second, "sham" group was treated daily by withdrawing 1 ml of wound fluid from the central dead space of the implant and then injecting the fluid back. In the third, hyperalimentation group the aspirated wound fluid was substituted with a corresponding volume of sterile, nonpyrogenic solution containing a mixture of amino acids (Le-7402 A) and glucose, electrolytes and vitamins (Le-7402 B). Within the first week of tissue growth daily application of these nutritional substances caused a changeover of local tissue from predominantly anaerobic towards more oxidative metabolism. Measurement of nucleic acid and hydroxyproline contents indicated enhanced accumulation of cells and collagen in tissues receiving local hyperalimentation. The results combined with earlier data from our laboratory strongly suggest that several types of wounds, especially those containing a marked dead space or large regenerative area, exist in chronic lack of oxygen and other nutrients. Therefore, the healing process in these wounds can be stimulated, to a certain extent, by exposure to increased oxygen tension and/or by local hyperalimentation.
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PMID:Local hyperalimentation of experimental granulation tissue. 2 Jul 23

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.
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PMID:Effects of intermittent and continuous hypoxia on the aortic wall in rabbits. 12 91

Collagen metabolism was studied in rat lungs during prolonged intermittent exposure to oxygen. After an initial of 2-d exposure to oxygen, the rats alternately breathed air and oxygen in 24-h periods up to 30 d. Lung histology showed perivascular edema as an early sign of oxygen toxicity. Increased capillary permeability was followed by a marked perivascular leukocytosis that was prominent between the 5th and 11th d of the treatment. During the further course of the experiment, the inflammatory response gradually diminished, and finally a network of collagen fibres filled the perivascular areas. The inflammatory process elevated the amounts of DNA and RNA in lung tissue, and the ratio of RNA to DNA was maximal on the 5th day. Studies on metabolism of lung collagen with intraperitoneally injected 3H-proline as label showed that, after the initial inflammatory reaction, both synthesis and degration of collagen were increased in oxygen-treated lungs. The increase in synthesis exceeded the rise in degradation and, therefore, collagen was accumulated. The activation of lung collagen synthesis coincided in time with a rise in the activity of lung protocollagen proline hydroxylase.
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PMID:Collagen metabolism in rat lungs during chronic intermittent exposure to oxygen. 16 7

A cross-sectional study was carried out to examine the activities of certain enzymes representing aerobic and anaerobic energy metabolism as well as the biosynthesis of collagen of M. vastus lateralis in 23 male endurance athletes in habitual training, aged 33 to 70 years. 23 sedentary healthy men of corresponding ages were selected for the control group. The mean maximal oxygen uptake of the trained subjects was 53.6 ml-kg--1. min--1 and that of the control subjects 36.3 ml-kg--1. min--1. As compared to the control group the trained subjects had significantly higher values in the muscle malate dehydrogenase, succinate dehydrogenase and prolyl hydroxylase activities, whereas the opposite was true in the activity of lactate dehydrogenase. In hexokinase and creatine phosphokinase no marked differences between the groups were observed. The results showed that endurance training leads to increased activities of oxidative enzymes in the skeletal muscle. The adaptation changes were also observed in old men. The increased activity of prolyl hydroxylase may reflect the general enzymatic adaptation to physical training. A possibility exists that the turnover of muscle collagen in endurance athelets is continuously faster than that in sedentary men of corresponding ages.
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PMID:Enzyme activities in muscle and connective tissue of M. Vastus lateralis in habitually training and sedentary 33 to 70-year-old men. 17 30

The brain area of female rats three months of age was exposed to 2 krd of X-rays, and various biochemical parameters were retermined as well as NAD(H) in vivo fluorescence of the brain surface after time intervals from one day to 18 months. During the early period, an increase in the uptake of alpha-aminobutyrate (AIB) and a temporary depression in beta-glucuronidase and cathepsin activity followed by an activation at one month was seen. Somewhat later, acid phosphatase increases. During the intermediate period, DNA and serotonin content and AIB uptake by brain increase, whereas AIB uptake by heart and muscle decreases. A fall in sialic acid content is also noted at this time. During the late phase collagen increases, AIB uptake by brain and liver decreases. No changes were found with respect to NAD(H) fluorescence and its response to breathing of low oxygen concentrations.
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PMID:Late effects in the central nervous system. A study of biochemical alterations after local exposure of the rat brain to 2 krd. 18 Jun 35

When exposed to low oxygen tension, in the absence of added ascorbic acid 3T6 mouse fibroblast cultures in late log phase respond by increased lactate production and increased hydroxylation of proline in nascent collagen, which is paralleled by an increase in prolyl hydroxylase activity. After 6 h recovery from the anoxic stimulus, however, cultures still yield more prolyl hydroxylase than controls, but the effect on hydroxylation of nascent collagen has disappeared. These observations help to dissect the dual role of ascorbate which can stimulate hydroxylation both by increasing the amount of active enzyme and by a cofactor-like role; in addition, these observations may be relevant to wound healing.
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PMID:The effect of hypoxia on collagen synthesis in cultured 3T6 fibroblasts and its relationship to the mode of action of ascorbate. 18 26

Traditionally, ligaments and tendons (L and T) have been regarded as metabolically inert structures. However, sufficient biochemical evidence on the metabolism of collagen has indicated that such a concept is no longer tenable. To determine whether L and T respond to increased or decreased levels of chronic exercise, studies were undertaken to measure their aerobic capacities. For comparative purposes, similar measurements were obtained from liver and skeletal muscles secured from normal and hypophysectomized male rats. Oxygen consumption and cytochrome oxidase (CO) activity was recorded from cell suspensions that had been prepared with the inclusion of collagenase and with elastase added to the medium. The O2 results showed that L and T had values that were approximately 10 times lower than liver tissue and 7.5 times less than the means from skeletal muscles. Hypophysectomy caused marked reductions in O2 uptake of liver and muscle tissues; but had no impact on L and T. When CO activity of these connective tissues were evaluated, immobilization and hypophysectomy caused significant reductions that ranged from -36% to -59% respectively. Training, on the other hand, resulted in increases of less than 10% in the activity of this enzyme within L and T while being elevated in muscle tissue by 58%. It was concluded that the metabolic activity of L and T was lowered with decreased levels of physical activity but it was unclear why chronic exercise did not produce the opposite effect.
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PMID:Physical activity and hypophysectomy on the aerobic capacity of ligaments and tendons. 20 28

Immunoglobulin-producing Merwin plasma cells, MPC-11, have been found to contain proplyl hydroxylase (prolyl-glycyl-peptide,2-oxoglutarate:oxygen oxidoreductase; EC 1.14.11.2) activity and its crossreacting protein, as well as hydroxyproline and a collagenous protein that could not be classified as type I, II, or III collagen. Friend leukemic cells, on the other hand, contained only prolyl hydroxylase. Thymus-derived (T) lymphocytes and bone-marrow-derived (B) lymphocytes freshly isolated from BALB/c mice expressed low but significant prolyl hydroxylase activity. Upon stimulation with phytohemagglutinin, the enzyme activity in T cells increased 22- to 29-fold. Crossreacting protein was also increased and appeared more stable than the prolyl hydroxylase. The effect of lipopolysaccharide stimulation on B cells uas similar but not as pronounced. Thus, even when not accompanied by other collagen biosynthetic activities, prolyl hydroxylase is present in all cells of hematologic origin.
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PMID:Expression of collagen biosynthetic activities in lymphocytic cells. 20 96

A general consideration of the pathogenesis of the various metabolic diseases which produce mental deficiency suggests that perturbation of the one carbon (folate) cycle may be important. Secondly, a review of diseases having some symptoms in common with trisomy 21 suggests the evidence of : a collagen disturbance (hypothyroidism and iminodipeptidurial) ; an oxygen disturbance (hypothyroidism and hemoglobinopathies) ; a cholinergic distrubance (Alzheimer's disease) ; a one-carbon-cycle disturbance (Lesch-Nyhan's disease). Thirdly, the peculiar pathology of trisomy 21 allows to find also a cholinergic disturbance and a disturbance close to the 10 formyl-tetrahydrololate entry of the folate cycle. Finally, an analysis of the possible effect of the excess of superoxide dismutase A and of the increase of glutathion peroxidase leads to the suspicion that a difficulty exists of dioxygenations and of non aromatic hydroxilations with a relative retardation of some FAD requiring reactions. A simplified scheme shows that these metabolic deviations could provoke a disturbance of the collagen and of synthesis of chemical mediators, in accordance with the indications furnished by the compared pathogenesis of the various affections studied. These heuristic reflexions open the way to further investigations.
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PMID:[Biochemical investigations and trisomy 21 (author's transl)]. 22 17

The activity of collagen prolyl hydroxylase in aortic wall was studied in rabbits exposed to chronic 10% ambient oxygen tension for 30 days. Prolyl hydroxylase in rabbit aorta was shown to be similar to the enzyme from other sources in that it required molecular oxygen, alpha-ketoglutarate, ferrous iron and ascorbate for its activity. The activity of prolyl hydroxylase was increased to 180% of controls in the intima-media samples from rabbits exposed to hypoxia. No atherosclerotic lesions could be seen in arteries of animals kept in chronic hypoxia. If the arteries of rabbits were injured with a single mechanical dilatation, the activity of prolyl hydroxylase increased more than 2-fold, as reported previously. The exposure of these animals to chronic hypoxia further elevated the prolyl hydroxylase activity.
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PMID:Increased collagen prolyl hydroxylase activity in the aortic wall of rabbits exposed to chronic hypoxia. 22 78


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