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

The effects of increased intracranial pressure (ICP) and increased cardiac output (QT) on the pulmonary vascular response to regional alveolar hypoxia were compared in pentobarbital-anesthetized, closed-chested dogs. A bronchial divider was inserted, the right lung (RL) was continuously ventilated with 100% O2, and the left lung (LL) was ventilated with either 100% O2 (hyperoxia) or a hypoxic gas mixture (hypoxia). Sulfur hexafluoride (SF6) was used to measure differential lung blood flow and the multiple inert gas technique assessed gas exchange. The response to LL alveolar hypoxia (hypoxic pulmonary vasoconstriction, HPV) was studied in each animal prior to, during, and after the ICP was increased by infusing mock cerebrospinal fluid (CSF) into a lateral ventricle so that cerebral perfusion pressure was 25 mmHg. During both control periods, QT was randomly altered by opening (high QT) or closing (normal QT) two arteriovenous fistulas. Increasing ICP significantly increased QT (P less than 0.01), pulmonary artery pressure (PAP) (P less than 0.05), and mixed venous oxygen tension (PVO2) (P less than 0.05), compared with normal QT controls. Opening the arteriovenous fistulas achieved similar increases in QT (P less than 0.01), PAP (P less than 0.05), and PVO2 (P less than 0.05). The percentage of blood flow to the LL (QL/QT%) during hyperoxia was 43.9 +/- 0.8% (mean +/- SE) and did not vary with manipulation of QT or ICP. QL/QT% during LL hypoxia was significantly increased by both increased ICP (24.6 +/- 3.5%) and high QT (23.1 +/- 1.0%) compared with normal QT (16.8 +/- 2.1) controls (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Effect of increased intracranial pressure on regional hypoxic pulmonary vasoconstriction. 231 30

Arterial pressure of chick embryos was measured electromanometrically to investigate the effect of altered gaseous environments on blood pressure (BP) and heart rate (HR). The experiments were made in eggs incubated for 14-16 days at 38 degrees C without impeding the diffusive respiratory gas exchange through the shell and chorioallantois. In air, the HR was counted 260-270 beats/min and the BP increased from 14/7 Torr at day 14 to 21/12 Torr at day 16. Both the BP and HR decreased with hypoxia, whereas hyperoxia affected a slight increase in BP and little change in HR. Hypercapnia decreased the HR and tended to enhance a systolic maximum pressure. The effect of hypoxia was augmented markedly in the presence of hypercapnia and vice versa. When N2 was replaced with helium (He), the effect of hypoxia was mitigated significantly. On the contrary, replacement of N2 with sulfur hexafluoride (SF6) augmented the effect of hypoxia. Because the respiratory gas exchange of the egg takes place by diffusion through the shell and chorioallantoic capillaries, the effect of He and SF6 atmospheres on BP and HR is attributed to an altered diffusivity of O2 and CO2 in these inert gases.
 ...
PMID:Effect of O2 and CO2 in N2, He, and SF6 on chick embryo blood pressure and heart rate. 679 62