A novel alveolar Krebs cycle-triggered CO2 sensing mechanism regulates regional pulmonary ventilation.

Pulmonary perfusion disorders provoke atelectasis in order to minimize ventilation/perfusion mismatch. However, the underlying mechanisms remain unknown. Because intraalveolar CO2 concentration ([CO2]iA) declines as a consequence of poor pulmonary perfusion we postulated the existence a novel alveolar CO2-sensing mechanism which adapts the ventilation to perfusion. Real-time fluorescence imaging of rat lungs revealed that low [CO2]iA decreased cytosolic and increased mitochondrial Ca2+ in alveolar epithelial cells (AEC), leading to reduction of surfactant secretion and alveolar ventilation. Mitochondrial inhibition by ruthenium red or rotenone blocked the hypocapnia-induced responses. In cultured Type 2 AEC hypocapnia decreased cytosolic Ca2+ independently from pH and increased the NADH production, the mitochondrial transmembrane potential, and subsequently the mitochondrial Ca2+ uptake. All responses were completely blocked by the gene knockdown of the NADH producing Krebs cycle enzyme isocitrate dehydrogenase. Furthermore, ligature of the pulmonary artery of rabbits decreased alveolar ventilation, surfactant secretion, and lung compliance. Addition of 5% CO2 to the inspiratory gas inhibited all responses. Accordingly, we provide evidence for a novel CO2-sensing mechanism of AEC regulated by the Krebs cycle activity in terms of a negative feedback loop adapting surfactant secretion and thus regional ventilation to pulmonary perfusion

Leukocyte sequestration in pulmonary microvessels and lung injury following systemic complement activation in rabbits

Inflammatory reactions are associated with sequestration of leukocytes in the lung. Complement activation leads to accumulation of leukocytes in alveolar septa and alveoli, to lung edema and hemorrhage. Although in organs other than the lung leukocytes interact with the vascular endothelium only in postcapillary venules, alveolar capillaries are considered to be the site of leukocyte sequestration in the lung. However, pulmonary venules and arterioles have not been investigated systematically after complement activation so far, A closed thoracic window was implanted in anesthetized rabbits; leukocytes and red blood cells were stained, and the movement of these cells was measured in superficial pulmonary arterioles, venules and alveolar capillaries using fluorescence video microscopy before and 30 and 60 min after infusion of cobra venom factor (CVF). Erythrocyte velocity and macrohemodynamic conditions did not change after CVF infusion and were not different from the sham-treated controls. The number of sticking leukocytes increased significantly compared to baseline and control: by 150% in arterioles and in venules and by 740% in alveolar capillaries within 60 min after CVF infusion. The width of alveolar septa in vivo was significantly enlarged after CVF infusion, indicating interstitial pulmonary edema. At the end of the experiments, myeloperoxidase activity was higher in the CVF group, showing leukocyte sequestration in the whole organ. It is concluded that complement activation by CVF induces leukocyte sequestration in lung arterioles, venules and alveolar capillaries and leads to mild lung injury

The change of value in selected accounting items due to the transition from the Czech accounting legislation to IFRS standards

katedra: KFÚ; rozsah: 102 s. (151 210 znaků)This diploma thesis is focused on a comparison of International Financial Reporting Standards with the Czech accounting legislation. The main goal is to prove the influence of the requirements of both systems on the reporting of the values of selected accounting items in the financial statements. The first chapter deals with the IFRS establishment history, their general requirements for the accounting system, which are listed in the Conceptual Framework and the comparison with the requirements of the Czech accounting legislation. The comparative analysis of measurement methods of assets and liabilities in the ambit of both accounting systems is performed in the second chapter. Chapter three compares the requirements for the financial statements drawn up in compliance with the IFRS and with the Czech accounting legislation. The analysis of influence of selected economic operations over the reporting in the balance sheet and the statement of profit or loss drawn up in compliance with the requirements of both systems is performed in the last chapter. Examined are the fields of the provisions, the expenses and revenues reporting of long-term contracts and the accounting amortization of intangible fixed assets.Tato diplomová práce je zaměřena na porovnání Mezinárodních standardů finančního výkaznictví (IFRS) s českou účetní legislativou. Hlavním cílem práce je prokázat odlišný vliv požadavků obou systémů na vykázání hodnoty vybraných účetních položek v účetních výkazech. První kapitola se zabývá historií vzniku standardů IFRS, jejich obecnými požadavky kladenými na účetní systém, které jsou uvedeny v Koncepčním rámci a srovnáním s požadavky české účetní legislativy. Ve druhé kapitole je provedena komparativní analýza způsobů oceňování majetku a závazků v rámci obou účetních systémů. Třetí kapitola porovnává požadavky kladené na účetní závěrku sestavenou dle standardů IFRS a dle české účetní legislativy. V poslední části je provedena analýza vlivu vybraných hospodářských operací na vykazování v rozvaze a výkazu zisku a ztráty sestavených dle požadavků obou systémů. Zkoumány jsou oblasti rezerv, vykazování nákladů a výnosů u dlouhodobých smluv a účetní odpisy dlouhodobého nehmotného majetku

IDH3 mediates apoptosis of alveolar epithelial cells type 2 due to mitochondrial Ca2+ uptake during hypocapnia

In adult respiratory distress syndrome (ARDS) pulmonary perfusion failure increases physiologic dead-space (VD/VT) correlating with mortality. High VD/VT results in alveolar hypocapnia, which has been demonstrated to cause edema formation, atelectasis, and surfactant depletion, evoked, at least in part, by apoptosis of alveolar epithelial cells (AEC). However, the mechanism underlying the hypocapnia-induced AEC apoptosis is unknown. Here, using fluorescent live-cell imaging of cultured AEC type 2 we could show that in terms of CO2 sensing the tricarboxylic acid cycle enzyme isocitrate dehydrogenase (IDH) 3 seems to be an important player because hypocapnia resulted independently from pH in an elevation of IDH3 activity and subsequently in an increase of NADH, the substrate of the respiratory chain. As a consequence, the mitochondrial transmembrane potential (ΔΨ) rose causing a Ca2+ shift from cytosol into mitochondria, whereas the IDH3 knockdown inhibited these responses. Furthermore, the hypocapnia-induced mitochondrial Ca2+ uptake resulted in reactive oxygen species (ROS) production, and both the mitochondrial Ca2+ uptake and ROS production induced apoptosis. Accordingly, we provide evidence that in AEC type 2 hypocapnia induces elevation of IDH3 activity leading to apoptosis. This finding might give new insight into the pathogenesis of ARDS and may help to develop novel strategies to reduce tissue injury in ARDS

Can ID Repetitive Elements Serve as Cis-acting Dendritic Targeting Elements? An In Vivo Study

Dendritic localization of mRNA/RNA involves interaction of cis-elements and trans-factors. Small, non-protein coding dendritic BC1 RNA is thought to regulate translation in dendritic microdomains. Following microinjections into cultured cells, BC1 RNA fused to larger mRNAs appeared to impart transport competence to these chimeras, and its 5′ ID region was proposed as the cis-acting dendritic targeting element. As these ID elements move around rodent genomes and, if transcribed, form a long RNA stem-loop, they might, thereby, lead to new localizations for targeted gene products. To test their targeting ability in vivo we created transgenic mice expressing various ID elements fused to the 3′ UTR of reporter mRNA for Enhanced Green Fluorescent Protein. In vivo, neither ID elements nor the BC1 RNA coding region were capable of transporting EGFP RNA to dendrites, although the 3′ UTR of α-CaMKII mRNA, an established cis-acting element did produce positive results. Other mRNAs containing naturally inserted ID elements are also not found in neuronal dendrites. We conclude that the 5′ ID domain from BC1 RNA is not a sufficient dendritic targeting element for mRNAs in vivo

Role of P-selectin in platelet sequestration in pulmonary capillaries during endotoxemia

Background: There is growing evidence that platelets accumulate in the lung and contribute to the pathogenesis of acute lung injury during endotoxemia. The aims of the present study were to localize platelet sequestration in the pulmonary microcirculation and to investigate the role of P-selectin as a molecular mechanism of platelet endothelial cell interaction. Methods: We used in vivo fluorescence microscopy to quantify the kinetics of fluorescently labeled erythrocytes and platelets in alveolar capillary networks in rabbit lungs. Results: Six hours after onset of endotoxin infusion we observed a massive rolling along and firm adherence of platelets to lung capillary endothelial cells whereas under control conditions no platelet sequestration was detected. P-selectin was expressed on the surface of separated platelets which were incubated with endotoxin and in lung tissue. Pretreatment of platelets with fucoidin, a P-selectin antagonist, significantly attenuated the endotoxin-induced platelet rolling and adherence. In contrast, intravenous infusion of fucoidin in endotoxin-treated rabbits did not inhibit platelet sequestration in pulmonary capillaries. Conclusion: We conclude that platelets accumulate in alveolar capillaries following endotoxemia. P-selectin expressed on the surface of platelets seems to play an important role in mediating this platelet-endothelial cell interaction. Copyright (c) 2006 S. Karger AG, Basel

Preclinical Evaluation of a Replication-Deficient Intranasal ΔNS1 H5N1 Influenza Vaccine

We developed a novel intranasal influenza vaccine approach that is based on the construction of replication-deficient vaccine viruses that lack the entire NS1 gene (ΔNS1 virus). We previously showed that these viruses undergo abortive replication in the respiratory tract of animals. The local release of type I interferons and other cytokines and chemokines in the upper respiratory tract may have a “self-adjuvant effect”, in turn increasing vaccine immunogenicity. As a result, ΔNS1 viruses elicit strong B- and T- cell mediated immune responses.), one dose of vaccine delivered intranasally was sufficient for the induction of antibodies against homologous A/Vietnam/1203/04 and heterologous A/Indonesia/5/05 H5N1 strains.Our findings show that intranasal immunization with the replication deficient H5N1 ΔNS1 vaccine candidate is sufficient to induce a protective immune response against H5N1 viruses. This approach might be attractive as an alternative to conventional influenza vaccines. Clinical evaluation of ΔNS1 pandemic and seasonal influenza vaccine candidates are currently in progress

Single HA2 Mutation Increases the Infectivity and Immunogenicity of a Live Attenuated H5N1 Intranasal Influenza Vaccine Candidate Lacking NS1

Our finding suggests that an efficient intranasal vaccination with a live attenuated H5N1 virus may require a certain level of pH and temperature stability of HA in order to achieve an optimal virus uptake by the nasal epithelial cells and induce a sufficient immune response. The pH of the activation of the H5 HA protein may play a substantial role in the infectivity of HPAIVs for mammals