An increased carbon dioxide production in transient hypoxia in healthy subjects at rest

Indices of pulmonary gas exchange and heart rate (HR) have been measured in 24 healthy subjects not adapted to hypoxia after hypoxic aerial mixture (HAM) (17, 15, 13 vol % of oxygen) respiration for 15 min. Using group data analysis, it has been shown that hypoxia under the conditions of inhalation of 17 and 15 vol % of O₂ caused no significant changes. Hypoxia under the conditions of 13 vol % of O₂ inhalation is a threshold one, when ventilation (SpO₂) drops below 85%. A significant increase in the lung ventilation (Ve) (10–14%, p < 0.05) and HR (11–15%, p < 0.05) have been observed in this case. Hyperpnea was accompanied by an increase in the oxygen uptake rate by 10% and carbon dioxide release rate (10–18%, p < 0.05). On the contrary, individual data analysis showed changes in the pulmonary gas exchange indices in 90% of subjects in the case of inhalation of 17 vol % of O₂ HAM. Four response types have been found: ventilation (increase in lung ventilation), hypoxic hypometabolism (decrease in oxygen consumption rate), and mobilization response (increase in oxygen utilization in the lungs), and anaerobic response, which is expressed in an increase in the carbon dioxide release rate along with an increase in the respiratory quotient. All these responses are of an individual type, but the ventilation response is developed in response to hypoxia caused by inhalation of 13 vol % of O₂ HAM and a decrease in SpO₂ below 85% in more than 60% of cases.     

Provision of nestboxes raises the breeding density of Great Tits Parus major equally in coniferous and deciduous woodland

Nestbox provision is a technique used to increase nest-site availability for secondary cavity-nesting birds. However, little is known about the demographic consequences of nestbox provision in different habitat types. To assess how nestbox provision affects the density of hole-nesting birds simultaneously in two contrasting habitats, we compared the breeding density of Great Tits along transects without nestboxes with that in transects where nestboxes were provided. Although the initial density of breeders was considerably higher in the deciduous habitat than in the coniferous habitat, provision of nestboxes increased density by a similar number of additional pairs in each habitat type. Thus, the provision of nestboxes in managed coniferous forests may be as effective in increasing the breeding opportunities of cavity nesters as in deciduous stands. Moreover, previous research showed that pairs in deciduous habitat with nestboxes have consistently lower breeding success than those in coniferous habitat with nestboxes. It is possible that the addition of nestboxes in the preferred habitat increased density to such an extent that density-dependent effects became apparent.     

The increase of carbon dyoxidi production at hypoxia in health subjects

Pulmonary gas exchange, SpO2 and heart rate at 15-min hypoxia (respiration by air with 0.17; 0.15 and 0.13 oxygen fractions) have been investigated in 24 health subjects. It has been established, results of the group analysis and the results of the individual analysis had been differed. Reaction on hypoxia at the group analysis had been found only at 0.13 02 fraction. It was only hyperventilation. The individual analysis had revealed 4 types of reaction on hypoxia already at 0.17 and 0.15 02 fractions: (1) hyperventilation, (2) decrease of oxygen consumption, (3) increase of ventilation effectiveness, (4) increase of CO2 production. The mechanisms of last reaction are unknown, but we supposed it was connected with anaerobic metabolism. The reactions were detected at light hypoxia (0.17 and 0.15 oxygen fractions) in 90% health subjects when SpO2 decreased to 87-93%. The increase ventilation has been detected at hypoxia within respiration 0.13 oxygen in 60% subjects when SpO2 decreased to 83-87%, while other reactions were nearly absent.     

The European Renal Genome Project: An Integrated Approach Towards Understanding the Genetics of Kidney Development and Disease

Rapid progress in genome research creates a wealth of information on the functional annotation of mammalian genome sequences. However, as we accumulate large amounts of scientific information we are facing problems of how to integrate and relate the data produced by various genomic approaches. Here, we propose the novel concept of an organ atlas where diverse data from expression maps to histological findings to mutant phenotypes can be queried, compared and visualized in the context of a three-dimensional reconstruction of the organ. We will seek proof of concept for the organ atlas by elucidating genetic pathways involved in development and pathophysiology of the kidney. Such a kidney atlas may provide a paradigm for a new systems-biology approach in functional genome research aimed at understanding the genetic bases of organ development, physiology and disease.Key Words: EuReGene, kidney, genome, development, pathophysiology, genetics     

Standardized estimation of external respiration function

External respiration in healthy males has, in addition to eupnea, six functionally active variants with one or several indices deviating from the normal values. Hyperpnea and hypopnea are determined by deviations in general oxygen consumption accompanied by adequate changes in pulmonary ventilation and gas exchange. Inhibition of gas exchange in the respiratory parts of the lungs is a typical primary event of hyperventilation, a fact indicated by a decrease in the coefficient of oxygen consumption and a compensatory increase in the minute respiratory volume during hyperventilation. Tension of the respiratory system is especially pronounced during enhanced oxygen consumption (O₂C). Highly effective bradypnea is characterized by infrequent and deep breathing. No tension of the respiratory system is observed even for increased O₂C. This state may be considered a genotypic and phenotypic variant of normal respiration. The data obtained may be used to automate the assessment of gas exchange in the respiratory parts of the lungs.