Oxygen delivery and utilization in dogs with a sublethal dose of cobalt chloride.

Four groups of eight dogs each were anesthetized with pentobarbital, paralyzed with succinylcholine, and ventilated at constant rate. Control measurements were made for 30 min, then 15 mg/kg of cobaltous chloride was given slowly intravenously to one group. A second group was also given 1 mg/kg per h propranolol (beta-block); a third group was given NaHCO3 to correct pH changes after CoCl2; and a fourth group had both beta-block and NaHCO3. Vo2 was measured every 10 min for 4 h and blood was taken frequently for lactate, pyruvate, and blood gas measurements. Cobalt transiently decreased Vo2 in all groups but significantly more in those with beta-block (groups 2 and 4). Cardiac output and mean arterial pressure were also decreased in all groups but to similar extent. Recovery of Vo2 was complete, usually within 60 min with little evidence of deficit repayment. Total O2 transport (Q X Cao2) appeared to limit Vo2 below 12 ml/kg times min. Above that value, histotoxic effects of CoCl2 reduced Vo2 approximately 20%. Excess lactate (XL) in arterial blood was linearly correlated with measured O2 deficit during the acute reaction of CoCl2, in all but group 3, similar to results previously obtained in hypoxic hypoxia.     

尼莫地平对犬体温过低性室颤的预防作用

目的：探讨尼莫地平对犬体温过低性室颤的预防作用。方法：雄性健康杂种犬随机分为给药组（n=3）和对照组（n=4）,冷水中全身性浸泡前后监测犬心功能指标和Ca2＋-ATP酶活性。结果：对照组出现室颤,而给药组未发生室颤。结论：尼莫地平有预防犬体温过低性室颤作用。     

Oxygen delivery through capillaries

During physical exertion the consumption rate increases and some cells suffer from the lack of oxygen. The time-wise evolution of hypoxia is analyzed mathematically under the condition the perfusion of each capillary is constant. The domain used contains multiple non-homogeneous capillaries of different solute out. Cells surrounding capillaries may consume or preserve more oxygen than are necessary at the beginning of new environment.     

Oxygen utilization by Lactobacillus plantarum

Cell-free extracts of Lactobacillus plantarum contain non-proteinaceous compounds which mimic superoxide dismutase activity. Using the test system in which O ₂ ^– is generated by xanthine oxidase, superoxide dismutase activity is found in cell-free extracts, where proteins are removed by precipitation. This activity is strongly decreased after dialysis of cell-free extracts. Superoxide dismutase activity was also investigated by means of pulse radiolysis. Cell-free extracts of Escherichia coli were also investigated as a comparison, which were known to contain superoxide dismutase. With cell-free extracts of both L. plantarum and E. coli the decay of O ₂ ^– was markedly increased. However, the type of reaction of the O ₂ ^– decay was of first order in the presence of E. coli extracts due to superoxide dismutase(s), and of second order in the presence of L. plantarum extracts, indicating that O ₂ ^– elimination is not an enzymic reaction. Mn²⁺ phosphate(s) might be responsible for the observed elimination of O ₂ ^– . The production of O ₂ ^– is not detectable during NADH-, lactate- or pyruvate oxidase reactions in L. plantarum extracts.     

Oxygen binding by marine fish blood under hypothermic experimental conditions

Influence of temperature in the range of 1-15 degrees C on oxygen binding properties of blood of thermophilic--golden mullet (Liza aurata), anchovy (Engraulis encrasicolus), and cold-tolerant--sardelle (Clupeonella cultriventris) fishes has been investigated under experimental conditions. Heat dependence of oxygenation reaction in thermophilic fish blood at temperature below 10 degrees C considerably increases, which is evidenced by high deltaH values. That is accompanied by a substantial increase of blood oxygen affinity and complicates blood deoxygenation at the tissue level. This reaction is apparently determined by the change of hemoglobin interaction with intraerythrocyte medium. The concentration of NTP in erythrocytes increases, that partially compensates negative changes of blood oxygen affinity (parameter P50 is raised) under long-term maintenance of fishes at 5 degrees C. However this reaction is not observed at low temperatures (1-2 degrees C).