Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0242706 (hyperoxia)
 5,219 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hyperpnoeic episodic breathing (HEB), a cyclic waxing and waning of breathing, has been widely reported in pre-term neonates, patients with Joubert syndrome and adults (Cheyne-Stokes respiration) with congestive heart failure and brainstem infarction. We now provide a developmental mouse model of neonatal HEB. We used retinoic acid (RA) (0.5-10 mg/kg of maternal weight) to alter embryonic development of the respiratory neuronal network at the onset of hindbrain segmentation (7.5 days post-coitum). HEB was observed in vivo after RA treatment during post-natal days 1-7 but not in control animals. HEB persisted after reduction of the chemoafferent input by hypocapnic hyperoxia (100% O(2)). A large increase and decrease of the rhythm resembling an HEB episode was induced in vitro by stimulating the parafacial respiratory oscillator in treated but not in control neonates. Post-natal localization of the superior cerebellar peduncle and adjacent dorsal tegmentum was found to be abnormal in the pons of RA-treated juvenile mice. Thus, early developmental specifications in the rostral hindbrain are required for the development of neurones that stabilize the function of the respiratory rhythm generator, thereby preventing HEB during post-natal maturation.
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PMID:Exposure to retinoic acid at the onset of hindbrain segmentation induces episodic breathing in mice. 1761 May 72

Rett syndrome (RTT) is a neurodevelopmental disorder caused by mutations in the X-linked gene methyl-CpG-binding protein 2 (Mecp2) that encodes a DNA binding protein involved in gene silencing. Periodic breathing (Cheyne-Stokes respiration) is commonly seen in RTT. Freely moving mice were studied with continuous recording of pleural pressure by telemetry. Episodes of periodic breathing in heterozygous Mecp2 deficient (Mecp2(+/-)) female mice (9.4 +/- 2.2 h(-1)) exceeded those in wild-type (Mecp2(+/+)) animals (2.5 +/- 0.4 h(-1)) (P = 0.010). Exposing Mecp2(+/-) animals to 40% oxygen increased the amount of periodic breathing from 118 +/- 25 s/30 min in air to 242 +/- 57 s/30 min (P = 0.001), and 12% oxygen tended to decrease it (67 +/- 29 s/30 min, P = 0.14). Relative hyperoxia and hypoxia did not affect the incidence of periodic breathing in Mecp2(+/+) animals. The ventilation/apnea ratio (V/A) was less at all levels of oxygen in heterozygous Mecp2(+/-) females compare with wild type (P = 0.003 to P < 0.001), indicating that their loop gain is larger. V/A in Mecp2(+/-) fell from 2.42 +/- 0.18 in normoxia to 1.82 +/- 0.17 in hyperoxia (P = 0.05) indicating an increase in loop gain with increased oxygen. Hyperoxia did not affect V/A in Mecp2(+/+) mice (3.73 +/- 0.28 vs. 3.5 +/- 0.28). These results show that periodic breathing in this mouse model of RTT is not dependent on enhanced peripheral chemoreceptor oxygen sensitivity. Rather, the breathing instability is of central origin.
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PMID:Effect of inspired oxygen on periodic breathing in methy-CpG-binding protein 2 (Mecp2) deficient mice. 1800 68