The use of oxygen therapy (high doses of oxygen - hyperoxia) in the treatment of premature infants results in their survival. However, it also results in a high incidence of chronic lung disease known as bronchopulmonary dysplasia, a disease in which airway hyper-responsiveness and pulmonary hypertension are well known as consequences. In our previous studies, we have shown that hyperoxia causes airway hyper-reactivity, characterized by an increased constrictive and impaired airway smooth muscle relaxation due to a reduced release of relaxant molecules such as nitric oxide, measured under in vivo and in vitro conditions (extra- and intrapulmonary) airways. In addition, the relaxation pathway of the vasoactive intestinal peptide (VIP) and/or pituitary adenylate cyclase activating peptide (PACAP) is another part of this system that plays an important role in the airway caliber. Peptide, which activates VIP cyclase and pituitary adenylate cyclase, has prolonged airway smooth muscle activity. It has long been known that VIP inhibits airway smooth muscle cell proliferation in a mouse model of asthma, but there is no data about its role in the regulation of airway and tracheal smooth muscle contractility during hyperoxic exposure of preterm newborns.
- MeSH
- bronchopulmonální dysplazie etiologie metabolismus patofyziologie MeSH
- gestační stáří MeSH
- hladké svalstvo metabolismus patofyziologie MeSH
- hyperoxie etiologie metabolismus patofyziologie MeSH
- hypofyzární adenylátcyklázu aktivující peptid metabolismus MeSH
- lidé MeSH
- modely nemocí na zvířatech MeSH
- novorozená zvířata MeSH
- novorozenec nedonošený * MeSH
- novorozenec MeSH
- oxygenoterapie škodlivé účinky MeSH
- plíce metabolismus patofyziologie MeSH
- předčasný porod * MeSH
- remodelace dýchacích cest MeSH
- signální transdukce MeSH
- vazoaktivní intestinální peptid metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- novorozenec MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
OBJECTIVES: Investigation of the effects of hyperoxia during resuscitation from hemorrhagic shock in swine with preexisting coronary artery disease. DESIGN: Prospective, controlled, randomized trial. SETTING: University animal research laboratory. SUBJECTS: Nineteen hypercholesterolemic pigs with preexisting coronary artery disease. INTERVENTIONS: Anesthetized, mechanically ventilated, and surgically instrumented pigs underwent 3 hours of hemorrhagic shock (removal of 30% of the calculated blood volume and subsequent titration of mean arterial blood pressure ≈40 mm Hg). Postshock resuscitation (48 hr) comprised retransfusion of shed blood, crystalloids (balanced electrolyte solution), and norepinephrine support. Pigs were randomly assigned to "control" (FIO2 0.3, adjusted for arterial oxygen saturation ≥ 90%) and "hyperoxia" (FIO2 1.0 for 24 hr) groups. MEASUREMENTS AND MAIN RESULTS: Before, at the end of shock and every 12 hours of resuscitation, datasets comprising hemodynamics, calorimetry, blood gases, cytokines, and cardiac and renal function were recorded. Postmortem, organs were sampled for immunohistochemistry, western blotting, and mitochondrial high-resolution respirometry. Survival rates were 50% and 89% in the control and hyperoxia groups, respectively (p = 0.077). Apart from higher relaxation constant τ at 24 hours, hyperoxia did not affect cardiac function. However, troponin values were lower (2.2 [0.9-6.2] vs 6.9 [4.8-9.8] ng/mL; p < 0.05) at the end of the experiment. Furthermore, hyperoxia decreased cardiac 3-nitrotyrosine formation and increased inducible nitric oxide synthase expression. Plasma creatinine values were lower in the hyperoxia group during resuscitation coinciding with significantly improved renal mitochondrial respiratory capacity and lower 3-nitrotyrosine formation. CONCLUSIONS: Hyperoxia during resuscitation from hemorrhagic shock in swine with preexisting coronary artery disease reduced renal dysfunction and cardiac injury, potentially resulting in improved survival, most likely due to increased mitochondrial respiratory capacity and decreased oxidative and nitrosative stress. Compared with our previous study, the present results suggest a higher benefit of hyperoxia in comorbid swine due to an increased susceptibility to hemorrhagic shock.
- MeSH
- analýza krevních plynů MeSH
- cytokiny metabolismus MeSH
- funkční vyšetření srdce MeSH
- hemodynamika MeSH
- hemoragický šok epidemiologie mortalita patofyziologie terapie MeSH
- hypercholesterolemie epidemiologie MeSH
- hyperoxie patofyziologie MeSH
- krevní tlak MeSH
- náhodné rozdělení MeSH
- nemoci koronárních tepen epidemiologie MeSH
- prasata MeSH
- prospektivní studie MeSH
- resuscitace metody MeSH
- vyšetření funkce ledvin MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
We investigated the influence of oxygenation of in vitro lung preparation on the pulmonary vascular reactivity. Small pulmonary vessels isolated from adult male Wistar rats exposed for 4 days to hypoxia (FiO2 = 0.1, group CH) were compared with those of normoxic controls (group N). The bath in the chamber of small vessel myograph was saturated with gas mixture containing either 21 % or 95 % of O2 with 5 % CO2 and we measured the reactions of vessels to acute hypoxic challenge with 0 % O2 or to PGF2?. We did not observe any difference of the contractile responses between both groups when the normoxic conditions were set in the bath. When the bath oxygenation was increased to 95 % O2, the contractions induced by hypoxic challenge and PGF2? decreased in chronically hypoxic rats and did not change in normoxic controls. We hypothesize that reduced reactivity of vessels from hypoxic rats in hyperoxia results from the effect of chronic hypoxia on Ca2+ signaling in the vascular smooth muscle, which is modulated by increased free radical production during the exposure to chronic hypoxia and further hyperoxia.
- MeSH
- arteria pulmonalis metabolismus patofyziologie účinky léků MeSH
- chronická nemoc MeSH
- dinoprost farmakologie MeSH
- financování organizované MeSH
- hyperoxie metabolismus patofyziologie MeSH
- hypoxie metabolismus patofyziologie MeSH
- krysa rodu rattus MeSH
- myografie MeSH
- potkani Wistar MeSH
- techniky in vitro MeSH
- vápníková signalizace MeSH
- vazokonstrikce účinky léků MeSH
- vazokonstriktory farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
Úvod: Principem hyperbarické oxygenoterapie je dýchání kyslíku za podmínek vyššího tlaku, než je tlak atmosférický. Behem expozice vysokým dávkám kyslíku se mohou vyskytnout projevy jeho toxických vlastností vyplývající z tvorby reaktivních forem kyslíku a dusíku. Cíl studie: Zjistit incidenci kyslíkové toxicity u pacientu lécených v našem centru v období let 1994–2005. Typ studie: Observacní retrospektivní. Výsledky: Ve sledovaném období bylo léceno celkove 4 164 pacientu s celkovým poctem 48 992 lécebných expozic. Bylo zaznamenáno 13 príznaku CNS toxicity u 7 pacientu, nejdramatictejší forma hyperoxických krecí se objevila u 4 pacientu s incidencí 0,08 promile. Srovnáním s výsledky predcházející práce z roku 1984 a analýzou vývoje incidence toxicity v ruzných obdobích byla sledována cetnost výskytu hyperoxických krecí v závislosti na aplikovaném lécebném tlaku. Záver: Hyperbarická oxygenoterapie je bezpecná a dobre tolerovaná metoda s ohledem na relativne nízkou incidenci projevu CNS toxicity. Incidence hyperoxických krecí v naší práci patrí k nejnižším mezi soucasne publikovanými studiemi. Jejich výskyt nevedl k poranení ci trvalým následkum.
Objective: Hyperbaric oxygen treatment is based on breathing pure oxygen under pressure higher than the ambient pressure. Signs of toxicity can occur due to the presence of oxygen and nitrogen reactive substances during exposure to high doses of oxygen. Aim of study: To find the incidence of oxygen toxicity in patients treated in our centre in 1994–2005. Design: Observational retrospective study. Results: 4,164 patients underwent total 48,992 treatment sessions in the period studied. Thirteen cases of toxicity occurred in 7 patients. The most dramatic symptom of oxygen CNS toxicity – hyperoxia-induced seizures – were observed in 4 patients (0.008%). The relation between hyperoxia-induced seizures and treatment pressure at different time periods was analysed and compared with the results of our previous study from 1984. Conclusion: Hyperbaric oxygen treatment is a safe and well tolerated method with a low incidence of CNS toxicity.The incidence of hyperoxia-induced seizures presented in our paper is almost the lowest of recently published studies. No injury or permanent sequelae were observed in relation to hyperoxia-induced seizures.
- MeSH
- centrální nervový systém chemie patofyziologie MeSH
- hyperbarická oxygenace metody statistika a číselné údaje škodlivé účinky MeSH
- hyperoxie komplikace patofyziologie MeSH
- lidé MeSH
- plíce fyziologie chemie patofyziologie MeSH
- reaktivní formy dusíku imunologie škodlivé účinky toxicita MeSH
- reaktivní formy kyslíku imunologie škodlivé účinky toxicita MeSH
- svalové křeče komplikace patofyziologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- srovnávací studie MeSH
- MeSH
- finanční podpora výzkumu jako téma MeSH
- hyperoxie etiologie patofyziologie MeSH
- karagenan aplikace a dávkování škodlivé účinky MeSH
- krysa rodu rattus MeSH
- modely nemocí na zvířatech MeSH
- pneumonie patofyziologie MeSH
- tyrosin analogy a deriváty krev škodlivé účinky MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- MeSH
- alanintransaminasa analýza krev MeSH
- aspartátaminotransferasy analýza krev MeSH
- hyperkapnie patofyziologie MeSH
- hyperoxie patofyziologie MeSH
- játra metabolismus zranění MeSH
- králíci MeSH
- kyslík metabolismus MeSH
- reperfuzní poškození patofyziologie MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
