Ratio of venous-to-arterial PCO2 to arteriovenous oxygen content difference during regional ischemic or hypoxic hypoxia

The purpose of the study was to evaluate the behavior of the venous-to-arterial CO2 tension difference (ΔPCO2) over the arterial-to-venous oxygen content difference (ΔO2) ratio (ΔPCO2/ΔO2) and the difference between venous-to-arterial CO2 content calculated with the Douglas’ equation (ΔCCO2D) over ΔO2 ratio (ΔCCO2D/ΔO2) and their abilities to reflect the occurrence of anaerobic metabolism in two experimental models of tissue hypoxia: ischemic hypoxia (IH) and hypoxic hypoxia (HH). We also aimed to assess the influence of metabolic acidosis and Haldane effects on the PCO2/CO2 content relationship. In a vascularly isolated, innervated dog hindlimb perfused with a pump-membrane oxygenator system, the oxygen delivery (DO2) was lowered in a stepwise manner to decrease it beyond critical DO2 (DO2crit) by lowering either arterial PO2 (HH-model) or flow (IH-model). Twelve anesthetized and mechanically ventilated dogs were studied, 6 in each model. Limb DO2, oxygen consumption ($${\dot{\text{V}}\text{O}}_{2}$$ V ˙ O 2 ), ΔPCO2/ΔO2, and ΔCCO2D/ΔO2 were obtained every 15 min. Beyond DO2crit, $${\dot{\text{V}}\text{O}}_{2}$$ V ˙ O 2 decreased, indicating dysoxia. ΔPCO2/ΔO2, and ΔCCO2D/ΔO2 increased significantly only after reaching DO2crit in both models. At DO2crit, ΔPCO2/ΔO2 was significantly higher in the HH-model than in the IH-model (1.82 ± 0.09 vs. 1.39 ± 0.06, p = 0.002). At DO2crit, ΔCCO2D/ΔO2 was not significantly different between the two groups (0.87 ± 0.05 for IH vs. 1.01 ± 0.06 for HH, p = 0.09). Below DO2crit, we observed a discrepancy between the behavior of the two indices. In both models, ΔPCO2/ΔO2 continued to increase significantly (higher in the HH-model), whereas ΔCCO2D/ΔO2 tended to decrease to become not significantly different from its baseline in the IH-model. Metabolic acidosis significantly influenced the PCO2/CO2 content relationship, but not the Haldane effect. ΔPCO2/ΔO2 was able to depict the occurrence of anaerobic metabolism in both tissue hypoxia models. However, at very low DO2 values, ΔPCO2/ΔO2 did not only reflect the ongoing anaerobic metabolism; it was confounded by the effects of metabolic acidosis on the CO2–hemoglobin dissociation curve, and then it should be interpreted with caution.

Grant as a legal form of innovation support: concept, content, difference from related categories

The author analyzes modern trends in state-legal construction in the Russian Federation, one of which is the focus on innovative activities. It is hypothesized that among the most effective forms of supporting innovation is a grant. The concept, essence, functional characteristic of a grant as a kind of privilege is studied. On the basis of the analysis of the legal doctrine, rules of law and law-enforcement practice the intrinsic lines of a grant allowing to carry out difference sides from adjacent categories of jurisprudence and institutes of the legislation, first of all, such as a subsidy, a grant and so forth stand out.

Design and creative activity of students in the process of distance learning in primary classes

The article is devoted to the characteristics of design and creative activity of students in the process of distance learning in primary classes. The article clarifies the concept and essence of project-creative activity of students, reveals its main stages, content, difference from project research activities of adults, features of project implementation by younger students, features of project implementation in the context of distance learning. It is established that the design and creative activity of primary school students in the course of distance learning is an activity with the use of distance educational technologies, aimed at solving educational and (or) scientific problems, creative tasks and tasks, the implementation of which is carried out on the basis of active problem-finding actions, creative self-realization of students and presented as the final result (project).

Regional venous–arterial CO2 to arterial–venous O2 content difference ratio in experimental circulatory shock and hypoxia

Background Venous–arterial carbon dioxide (CO2) to arterial–venous oxygen (O2) content difference ratio (Cv-aCO2/Ca-vO2) > 1 is supposed to be both sensitive and specific for anaerobic metabolism. What regional hemodynamic and metabolic parameters determine the ratio has not been clarified. Objectives To address determinants of systemic and renal, spleen, gut and liver Cv-aCO2/Ca-vO2. Methods Post hoc analysis of original data from published experimental studies aimed to address effects of different fluid resuscitation strategies on oxygen transport, lactate metabolism and organ dysfunction in fecal peritonitis and endotoxin infusion, and from animals in cardiac tamponade or hypoxic hypoxia. Systemic and regional hemodynamics, blood flow, lactate uptake, carbon dioxide and oxygen-derived variables were determined. Generalized estimating equations (GEE) were fit to assess contributors to systemic and regional Cv-aCO2/Ca-vO2. Results Median (range) of pooled systemic Cv-aCO2/Ca-vO2 in 64 pigs was 1.02 (0.02 to 3.84). While parameters reflecting regional lactate exchange were variably associated with the respective regional Cv-aCO2/Ca-vO2 ratios, only regional ratios were independently correlated with systemic ratio: renal Cv-aCO2 /Ca-vO2 (β = 0.148, 95% CI 0.062 to 0.234; p = 0.001), spleen Cv-aCO2/Ca-vO2 (β = 0.065, 95% CI 0.002 to 0.127; p = 0.042), gut Cv-aCO2/Ca-vO2 (β = 0.117, 95% CI 0.025 to 0.209; p = 0.013), liver Cv-aCO2/Ca-vO2 (β = − 0.159, 95% CI − 0.297 to − 0.022; p = 0.023), hepatosplanchnic Cv-aCO2/Ca-vO2 (β = 0.495, 95% CI 0.205 to 0.786; p = 0.001). Conclusion In a mixed set of animals in different shock forms or during hypoxic injury, hepatosplanchnic Cv-aCO2/Ca-vO2 ratio had the strongest independent association with systemic Cv-aCO2/Ca-vO2, while no independent association was demonstrated for lactate or hemodynamic variables.

Perspectivism of the Renaissance Thought

The starting point of the essay is clarifying the difference between the mono-perspective and multi-perspective vision of reality. Off-course the terms perspective, mono-perspective and multi-perspective are not self-explanatory and the meanings of these terms need to be formally analysed. After making the formal difference between mono-perspective thinking and multi-perspective thinking a content difference needs to be made. Namely, why is the Renaissance vision of reality multi-perspective and the Middle-Age vision of reality mono-perspective? The answer to this question needs to be given by the analysis of the original works of the Renaissance thinkers. Our undertaking will not be limited in analysing only one discourse but following the subject from a methodological point of view in a multi-perspectivism way. Therefore, three different discourses will be analysed: The discourse of philosophical anthropology with Mirandola’s vision of man as a paradigmatic example-The discourse of philosophy of nature, with Bruno’s vision of the universe as a paradigmatic example-The discourse of art history in which four paintings will be analysed: these paintings can be considered of having philosophical, value because they provide a picturesque representation of what the Renaissance “world” was really like.