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Query: UMLS:C0242706 (hyperoxia)
 5,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The content of homocarnosine, gamma-amino butyric acid and histidine was studied in the brain of newborn, 1, 7, 14, 21 and 30-day rabbits in normalcy and under hyperoxia. For 30 days of the postnatal life the amount of peptide in the animal brain is 2.5, histidine 1.6, gamma-amino butyric acid--2.2 times as high. At the preconvulsive stage of oxygen poisoning the content of homocarnosine lowers sharply in the brain of rabbits of all age groups. The most considerable decrease is observed in the brain of 14, 21 and 30-day rabbits by 53, 60 and 85%, respectively. The content of gamma-amino butyric acid lowers only in the brain of 21 and 30-day animals by 39 and 47%, respectively; the content of histidine in these animals under hyperoxia, vice versa, increases by 10 and 25%.
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PMID:[Content of homocarnosine, gamma-amino butyric acid and histidine in brain tissue of different age normal rabbits and under hyperoxia]. 45 27

Water-insoluble proteins of rat brain were studied as affected by hyperbaric oxygenation (oxygen pressure 6 at.ga. convulsion state). Solubilization of proteins under effect of hyperoxia and triton X-100 increases by 32-81%. Changes in the amino acidic composition of proteins extracted by 0.5% triton X-100 are characterized by an increase in the amount of aspartic acid, cystin, leucine and isoleucine and by a decrease in the amount of histidine, arginine and methionine. Electrophoresis in 7.5% polyacrylamide gel of proteins in the 0.5% triton X-100 extract showed changes in the number and mobility of protein bands.
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PMID:[Effect of hyperoxia on water-insoluble proteins of the brain]. 68 68

The content of homocarnosine, GAMA, histidine, glutaminic acid and activity of glutamate decarboxylase were studied in four regions of rats brain: cerebral hemispheres, midbrain, diencephalon and cerebellum, in norm and under hyperoxia. A considerable decrease in the content of homocarnosine, GAMA and histidine is observed in all the studied regions of the rat brain in the convulsion stage of oxygen poisoning. A decrease in the glutamate decarboxylase activity is the reason for a drop in the GAMA content. Homocarnosine in the brain is bound functionally with the GAMA level.
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PMID:[Metabolism of homocarnosine and gamma-amino butyric acid in different regions of rat brain under hyperoxia]. 72 92

Adult male Wistar rats were submitted to normobaric hyperoxygenation for 1 and 4 hours, then brain synaptosomes were isolated and uptake and release of the histamine precursor - histidine (His), histamine (HA) level and His metabolizing enzymes activities were measured. This uptake in hyperoxic synaptosomes was inhibited by about 20%. After 1-hour hyperoxia, a tendency towards an increase of the HA level, but a significant increase histidine decarboxylase (HD) and histamine methyltransferase (HMT) activities were observed. Four-hour hyperoxia caused a decrease of both the HA level and the activities of both enzymes, especially HMT. The changes were reversed in 1-hour posthyperoxic recovery, except for histidine uptake which remained inhibited.
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PMID:Effect of hyperoxia on histamine metabolism in rat brain synaptosomes: preliminary observations. 181 16

We have studied the effect of various compounds, known as antioxidants, on the level of hyperoxia (80-90% O2)-induced chromosomal aberrations in Chinese hamster ovary cells: ascorbic acid, alpha-tocopherol, carnosine, imidazole-4-acetic acid, glutathione monoethylester, N-acetylcysteine and ethoxyquin. Carnosine (beta-alanyl-histidine) appeared to be the only compound that reduced chromosomal breakage. The effect was also present in cultures post-treated with caffeine (at 2.5 mM, 3 h before harvest), indicating that the apparent protection was not due to selective arrest of chromosomally damaged cells in the G2 phase of the cell cycle. Imidazole-4-acetic acid, a compound structurally very similar to carnosine, had no detectable effect. Ascorbic acid, N-acetylcysteine, glutathione monoethylester and ethoxyquin were found to have a pro-oxidant effect, i.e. they apparently potentiated the clastogenic effect of hyperoxia. Carnosine is the first compound shown to protect against the clastogenicity of normobaric hyperoxia and may thus be a useful tool in elucidating the underlying mechanism.
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PMID:Effect of antioxidants on hyperoxia-induced chromosomal breakage in Chinese hamster ovary cells: protection by carnosine. 194 22

A full-length hemopexin cDNA was isolated from a rat liver cDNA library and the derived amino acid sequence was obtained. Rat hemopexin shows a 76% amino acid homology with human hemopexin. The amino-terminal domain of rat hemopexin contains two histidine residues that are conserved in the human and rat sequences and are the most likely heme axial ligands. Analogous to human hemopexin, the rat hemopexin consists of 10 internal repeating peptide motifs characteristic of the pexin gene family. A complete conservation of cysteine residues is seen between the human and rat sequences suggesting an identical disulfide bridge structure in both proteins. Our analysis of the primary structure of rat hemopexin reveals characteristics typical for members of the pexin gene family and suggests a conserved evolutionary role for the C-terminal (non-heme-binding) domain of this protein. The full-length rat hemopexin cDNA was used to analyze changes in hemopexin gene expression during development and experimental inflammation. RNA blot analysis showed a single 2.0-kb hemopexin mRNA present in fetal liver at day 14. Hemopexin-specific mRNA was not detected in embryonic or fetal tissues at earlier stages of development and was confined to the liver throughout fetal, newborn, and adult life. The abundance of hemopexin mRNA was found to increase throughout gestation, with a sharp increase in the first postnatal weeks, reaching maximum levels in adult animals. Endotoxin-induced inflammation resulted in a 5-fold increase in hepatic hemopexin mRNA content within 48 h without associated changes in hemopexin transcript size. Adult animals exposed to hyperoxia (95% oxygen) showed a 3-fold increase in hepatic hemopexin mRNA content.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Rat hemopexin. Molecular cloning, primary structural characterization, and analysis of gene expression. 198 69

A study was made of the blood and tissue oxygen regime in patients with vibratory disease (VD) induced by local vibration and of the importance of lipid peroxidation (LPO) in oxygenation disorders. Venous hyperoxia, a decrease of the arteriovenous difference according to oxygen, the percentage of oxygen utilization by tissues, shift of the acid-base balance towards metabolic acidosis were established, attesting to tissue hypoxia that increased with the gravity of VD. The importance of a steady activation of LPO and depression of the antioxidant system in the pathogenesis of hypoxia associated with VD was supported by the correlation analysis data on oxygen balance and LPO, the functional and metabolic characteristics of red blood cells (according to the viscosity of red blood cell suspension and the content in the cells of SH-groups, lipoproteins and histidine) and platelets (according to aggregation in response to ADP and thrombin) as well as by the level of blood serum fluorescence. The authors provide evidence for the use of antioxidants (a complex of alpha-tocopherol with ascorbic acid and methionine and calcium antagonists of the nifedipine group), giving a membranostabilizing effect, in multimodality treatment of patients afflicted with VD.
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PMID:[Cell-membrane aspects of the pathogenesis of hypoxia in vibration disease induced by local vibration]. 204 32

Dynamics of biologically active brain peptides: N-acetyl-1-aspartat-1-glutamat (NAAG) and homocarnosine (gamma-aminobutyric-1-histidine), aminoacids and their derivatives GABA, histidine and histamine, in the blood of rats and rabbits of different age under hyperoxia was studied. Exposure of animals to 4 atm of oxygen considerably decreased NAA and NAAG contents in the brain of 21 and 30-day old rats and induced the 85% and 47% decrease of homocarnosine and GABA contents respectively in the brain of 30-day old rabbits. Brain histidine and blood histamine contents increased in 14, 21 and 30-day old rabbits.
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PMID:[Age and the role of certain mediators in the sensitivity of animals to hyperbaric oxygenation]. 610 64

Patients treated with bleomycin (BLM) are at risk of developing acute respiratory distress syndrome (ARDS) post-operatively, and this has been associated with high intraoperative concentrations of oxygen. We report progressive arterial desaturation noticeable 2 h after the start of a 4-h radical neck dissection for which the anaesthesia included 50% O2 in N2O. The patient had received two courses of bleomycin within the previous 2 months and had undergone an uneventful right hemiglossectomy under shorter but otherwise similar anaesthesia 4 weeks previously. His pulmonary function tests before the second procedure showed a slight depression of diffusing capacity (DLco) to 80% of predicted and minimal airway obstruction consistent with his history of smoking. The pulse oximetric reading during his second procedure reached 75%, but rose to 95% after treatment with methylprednisolone salbutamol and inspired O2 concentrations between 80% and 100%. By the end of the procedure, he satisfied the criteria for ARDS and was transferred to the ICU, where he developed bilateral pneumonia, deteriorated and died of multiple organ failure. This case suggests that the risk of hyperoxic pulmonary damage in patients exposed to bleomycin may increase not only with the degree and duration of hyperoxia in a given exposure, but also with the latent effects of recent previous exposure. Near normality of pulmonary function tests cannot be taken as reassurance, and small changes may have more adverse prognostic significance than in patients who have not been exposed to bleomycin.
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PMID:Intraoperative respiratory failure in a patient after treatment with bleomycin: previous and current intraoperative exposure to 50% oxygen. 1008 4