Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020440 (hypercapnia)
 7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this study was twofold: (1) to define the relationship between erythropoietin (Ep) production and some of the coincident variables which control oxygen delivery in hypoxic and hypoxic-hypercarbic rats (2) to define the mechanism whereby hypercarbia suppresses Ep production in hypoxemic rats. Rats were exposed to O2 concentrations ranging from 5% to 9% O2 for either 3 or 16 h. Arterial whole blood pH, pCO2, pO2, O2 saturation, p50 and Ep levels were measured in each rat. There was a highly significant inverse correlation between both the arterial pO2 and O2 saturation and the Ep level. Ep levels were not increased above normal if the pO2 was greater than 50 mm Hg or the O2 saturation was greater than 80%. The addition of 5% CO2 to all inhaled gas mixtures was associated with a 10 mm Hg increment in the pO2 together with a marked reduction in plasma Ep levels. Of the measured variables only the pO2 and O2 saturation showed a consistent correlation with the Ep levels when rats exposed to hypoxia were compared with rats exposed to hypoxia + CO2.
 ...
PMID:Regulatory mechanism of erythropoietin production: effects of hypoxemia and hypercarbia. 678 9

The hemoglobin-oxygen dissociation curve and the relationships between the parameters of tension, saturation, capacity, affinity and concentration of oxygen in the course of respiratory failure in chronic obstructive lung diseases (COLD) were studied. The study included 141 patients divided into four basic groups according to the value of pO2 (a): patients with normoxia, mild, moderate and severe arterial hypoxia. The blood-gas status was determined using the ABL-330 and OSM-3 analyzers (Radiometer A/S, Denmark). It is concluded that: 1. Presence of normoxia (pO2 and sO2 in norm) in COLD patients does not exclude abnormalities in their arterial blood oxygen transport and increased risk of tissue hypoxia. 2. Total oxygen concentration in respiratory failure is relatively stable and "independent" from the stepwise decrease of the arterial pO2, which results from the compensatory increase of the total and effective hemoglobin. 3. There are phase fluctuations of the ctO2/pO2 dissociation curve in the reference interval, expressed in the "lowering" of P50 and p90 in mild hypoxia and the "centering" or "raising" of their values in severe hypoxia. Such fluctuations are more pronounced in the p90 than in the p50. 4. The oxygen extraction tension lowers progressively (without reaching the anaerobic threshold) and the oxygen compensation factor elevates with the pO2 (a) reduction and the arising of hypercapnia and acidemia. 5. The calculated 2,3-diphosphoglycerate (2,3-DPG) concentration values are significantly higher in hypercapnics with COHb > 1% than in those with COHb < 1%. The relationships between hypoxia, oxygen affinity, hemoglobinemia and oxygen affinity as well as the dissociation curve properties in chronic respiratory failure are discussed.
 ...
PMID:Relationships between blood oxygen parameters in patients with chronic obstructive lung disease. 819 1

The effects of a continuous infusion of tris(hydroxymethyl)aminomethane (THAM) on pH, base excess, p50, serum osmolality, and plasma drug concentration during respiratory acidosis were studied in newborn piglets. Measurements were made during three experimental periods: (1) control period with normal blood gases; (2) hypercapnia period, and (3) hypercapnia plus THAM period (THAM infusion: 1.65 mmol/kg/h). pH decreased and paCO2 increased between control period (7.40 +/- 0.05 and 45 +/- 3 mm Hg) and hypercapnia period (7.24 +/- 0.06 and 59 +/- 2 mm Hg; p < 0.001; mean +/- SD). pH returned to baseline (7.37 +/- 0.04) during the hypercapnia plus THAM period, while paCO2 remained elevated (63 +/- 4 mm Hg). p50 increased from 30.7 +/- 5.9 to 38.3 +/- 4.7 (p < 0.05) during hypercapnia and decreased with hypercapnia plus THAM. THAM concentration and base excess increased with time and were linearly related. Serum osmolality was unchanged during the THAM infusion. We conclude that continuous infusion of THAM is effective in normalizing pH during respiratory acidosis in the piglet.
 ...
PMID:Effects of a continuous infusion of tris(hydroxymethyl)aminomethane on acidosis, oxygen affinity, and serum osmolality. 829 38

Oxygen supply was corrected in rabbits during the hepatic ischemia/reperfusion by means of different breathing mixtures: hypoxic (14.8 % O(2)+85.2 % N(2)), hyperoxic (78 % O(2)+20.2 % N(2)+ 1.8 % CO(2)), or hypercapnic (5 % CO(2) in air). Hepatic ischemia was induced for 30 min by ligation of hepatic artery, reperfusion period lasted 120 min. Indices of blood oxygen transport (p50(act), pCO(2), pH, pO(2), etc.) and prooxidant-antioxidant balance (Schiff bases, conjugated dienes, catalase, retinol, alpha-tocopherol) were measured in the blood and liver. The severity of reperfusion damage was evaluated by the activities of alanine and aspartate aminotransferases (ALT, AST) in the blood. Hepatic ischemia/reperfusion resulted in higher p50(act) in hepatic venous and mixed venous blood in all experimental groups. The changes of p50(act) were most marked in the hypercapnic group and were the weakest in the hypoxic group. The rise in p50(act) was accompanied by higher levels of lipid peroxidation products, ALT and AST in blood and liver homogenates, and by a simultaneous fall of alpha-tocopherol and retinol concentrations, except in the hypoxic group. Catalase activity at the end of reperfusion increased under normoxia, decreased under hyperoxia or hypercapnia and did not change under hypoxia. The moderate hypoxia during reperfusion was accompanied by a better balance between the mechanisms of reactive oxygen species production and inactivation that may be observed by optimal changes in p50act and reduced the hepatic damage in this pathological condition.
 ...
PMID:Influence of different oxygen modes on the blood oxygen transport and prooxidant-antioxidant status during hepatic ischemia/reperfusion. 1453 28