Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020440 (hypercapnia)
7,939 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Severe blunt chest trauma remains an important injury with high morbidity and mortality. However, the associated immunological alterations are poorly understood. Existing big animal models require large-scale settings, are often too expensive, and research products for immunological studies are limited. In this study we aimed to establish a new model of blunt, isolated and bilateral chest trauma in mice and to characterize its effects on physiological and inflammatory variables. Male C3H/HeN mice (n = 9-10/group) were anesthetized and a femoral artery was catheterized. The animals were subjected to trauma or sham procedure and monitored for 180 min. Blunt chest trauma was induced by a blast wave focused on the thorax. Trauma intensity was optimized by varying the exposure distance. Blood pressure, heart rate, respiratory rate, arterial blood gases and plasma cytokine levels were measured. Macroscopic and microscopic examinations were performed. In addition, outcome was evaluated in a 10-day survival study. Chest trauma caused a drop (P < 0.05) in blood pressure and heart rate, which partly recovered. Blood gases revealed hypoxemia and hypercarbia (P < 0.05) 180 min after trauma. There was marked damage to the lungs but none to abdominal organs. Histologically, the characteristic signs of a bilateral lung contusion with alveolar and intrabronchial hemorrhage were found. Plasma interleukin-6 and tumor necrosis factor alpha were considerably increased after 180 min. Blunt chest trauma resulted in an early mortality of 10% without subsequent death. On the basis of these findings, this novel mouse model of blunt chest trauma appears suitable for detailed studies on immunological effects of lung contusion.
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PMID:Cardiopulmonary, histological, and inflammatory alterations after lung contusion in a novel mouse model of blunt chest trauma. 1475 96

Muscular dystrophy is associated with inflammation and fiber necrosis in the diaphragm that may alter ventilatory function. The purpose of this study was to determine to what extent in vivo ventilatory function in dystrophic (mdx) mice was compromised and to assess the impact of deletion of tumor necrosis factor-alpha (TNF-alpha), a known proinflammatory cytokine, on ventilatory function, diaphragm contractility, and myosin heavy chain (MHC) distribution in 10-12-month-old mdx mice. Although the resting ventilatory pattern did not significantly differ between control and mdx mice, the ventilatory response to hypercapnia in mdx mice was significantly attenuated. Elimination of TNF-alpha significantly improved the hypercapnic ventilatory response and diaphragm muscle maximal isometric force. Long-term TNF-alpha deletion also altered the myosin heavy chain isoform profile of the diaphragm. These data indicate that a blunted ventilatory response to hypercapnia exists in mdx mice, and that TNF-alpha influences the progressive deterioration of diaphragm muscle in mdx mice.
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PMID:Ventilatory dysfunction in mdx mice: impact of tumor necrosis factor-alpha deletion. 1292 94

Respiratory failure occurs due mainly either to lung failure resulting in hypoxaemia or pump failure resulting in alveolar hypoventilation and hypercapnia. Hypercapnic respiratory failure may be the result of mechanical defects, central nervous system depression, imbalance of energy demands and supplies and/or adaptation of central controllers. Hypercapnic respiratory failure may occur either acutely, insidiously or acutely upon chronic carbon dioxide retention. In all these conditions, pathophysiologically, the common denominator is reduced alveolar ventilation for a given carbon dioxide production. Acute hypercapnic respiratory failure is usually caused by defects in the central nervous system, impairment of neuromuscular transmission, mechanical defect of the ribcage and fatigue of the respiratory muscles. The pathophysiological mechanisms responsible for chronic carbon dioxide retention are not yet clear. The most attractive hypothesis for this disorder is the theory of "natural wisdom". Patients facing a load have two options, either to push hard in order to maintain normal arterial carbon dioxide and oxygen tensions at the cost of eventually becoming fatigued and exhausted or to breathe at a lower minute ventilation, avoiding dyspnoea, fatigue and exhaustion but at the expense of reduced alveolar ventilation. Based on most recent work, the favoured hypothesis is that a threshold inspiratory load may exist, which, when exceeded, results in injury to the muscles and, consequently, an adaptive response is elicited to prevent and/or reduce this damage. This consists of cytokine production, which, in turn, modulates the respiratory controllers, either directly through the blood or probably the small afferents or via the hypothalamic-pituitary-adrenal axis. Modulation of the pattern of breathing, however, ultimately results in alveolar hypoventilation and carbon dioxide retention.
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PMID:Respiratory failure. 1462 Nov 12

Hypertrophic osteoarthropathy (HOA) is a condition that accompanies many seemingly unrelated diseases. It is commonly associated with various clinical conditions such as pregnancy, aging, pulmonary diseases, cancers, and other systemic illnesses. The condition has been attributed to various causes such as platelet abnormalities, hormonal disturbances, and cytokine dysfunction, but the exact underlying mechanism has been elusive. We propose a unifying hypothesis that activation of the adrenergic system is the common thread that links all of the disparate clinical associations of hypertrophic osteoarthropathy. In diseased states, autonomic stimulation may occur as a result of chemoreceptor activation in response to acidosis, hypoxia, or hypercapnia. Examples include sleep apnea, congestive heart failure, renal failure, and tumor-induced hypoxia. In this setting, clinical signs of HOA may be a marker of underlying autonomic dysfunction. Autonomic stimulation may also occur as a normal part of pregnancy or as an abnormal component of aging. The exact pathway linking adrenergic excess to HOA remains to be clarified, but a plausible scenario based on current molecular evidence is offered.
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PMID:Hypertrophic osteoarthropathy may be a marker of underlying sympathetic bias. 1523 3

The influence of haemorrhage and resuscitation on Tumour Necrosis Factor (TNF) production by whole blood cultures under endotoxin (Escherichia coli LPS) stimulation was investigated in male BALB/c mice. Haemorrhagic shock was induced by removing 0.026 +/- 0.003 mL of blood/g via a cardiac puncture, resulting in a 50% decrease in arterial pressure and a metabolic adidosis. Animals were resuscitated successfully (normotensive) despite a residual base deficit and hyperlactatemia, 60 min after the haemorrhage by the restitution of shed blood volume (SBV) with or without an additional volume of crystalloid (Lactated Ringer's solution) equal to 50, 100 (isovolumetric resuscitation) or 200% of SBV. Pulmonary failure (hypoxia-hypercarbia) and myocardial injury (troponin I release) was observed in this last group. TNF production by whole blood cultures stimulated ex vivo by LPS was estimated 60 min after the end of resuscitation. Haemorrhage resulted in a 48-60% decrease in TNF production. This decrease so-called 'leukocyte deactivation' was not modified by the restitution of SBV with or without crystalloid except for isovolumetric resuscitation which resulted in the cytokine level returning to control in the absence of clear cardiopulmonary dysfunction. In the present murine model of haemorrhage, modifying resuscitation volume influences in vitro TNF production in whole blood cultures challenged by LPS.
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PMID:Influence of resuscitation volume on blood cells TNF production in a murine model of haemorrhage. 1621 9

Increasing evidence indicates that there exists a reciprocal communication between the immune system and the brain. Interleukin 1beta (IL-1beta), a proinflammatory cytokine produced during immune challenge, is believed to be one of the mediators of immune-to-brain communication, but how it gets into the brain is unknown because of its large molecular weight and difficulty in crossing the blood-brain barrier. Our previous work has demonstrated that IL-1 receptor type I is strongly expressed in the glomus cells of rat carotid body (CB), a well characterized polymodal chemoreceptive organ which serves not only for the detection of hypoxia, hypercapnia and acidity, but also for low temperature and blood glucose. The present study was designed to test whether IL-1beta could stimulate the CB glomus cells and alter the discharge properties in the carotid sinus nerve, the afferent nerve innervating the organ. The results from whole-cell patch-clamp recordings and calcium imaging showed that extracellular application of IL-1beta significantly decreased the outward potassium current and triggered a transient rise in [Ca(2+)](i) in the cultured glomus cells of rat CB. Furthermore, by using extracellular recordings and pharmacological intervention, it was found that IL-1beta stimulation of the CB in the anaesthetized rat in vivo significantly increased the discharge rate in the carotid sinus nerve, most probably mediated by ATP release. This experiment provides evidence that the CB responds to cytokine stimulation and proposes the possibility that the CB might play a role in immune-to-brain communication.
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PMID:IL-1beta inhibits IK and increases [Ca2+]i in the carotid body glomus cells and increases carotid sinus nerve firings in the rat. 1761 May 83

Cell stretch stimulates both surfactant and cytokine production. The authors proposed that stretch, through these effects, modifies the pathogenesis of lipopolysaccharide-induced acute lung injury (ALI), and that this is CO(2) dependent. Rat alveolar type II cells and macrophages were co-cultured with lipopolysaccharide in 5%, 10%, or 20% CO(2) +/- stretch (30%, 60 cycles/min) for 6 hours. Intracellular TNF-alpha and IL-6 increased whereas secreted cytokine and surfactant decreased with increasing CO(2). Stretch independently increased intracellular TNF-alpha and decreased IL-6 secretion. Elevated CO(2) may therefore diminish secretion of proinflammatory cytokines by alveolar cells, contributing to an explanation for protective hypercapnia in ALI.
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PMID:Intracellular storage of surfactant and proinflammatory cytokines in co-cultured alveolar epithelium and macrophages in response to increasing CO2 and cyclic cell stretch. 1820 76

Carbon dioxide (CO(2)) interacts in complex ways with the brain and the endocrine and immune systems. Arterial CO(2) may be elevated or decreased following cerebral ischemia-reperfusion injury or stroke. The aim of the present review is to delineate potential changes in the neuroimmunoendocrine system following cerebral ischemia-reperfusion injury and to provide evidence for the modulatory role of carbon dioxide in this setting. It appears that lesions of the right and left cerebral hemispheres are associated with different patterns of immune activation and cytokine release. Changes in arterial CO(2) can profoundly alter the neuroimmunoendocrine system, especially the hypothalamic-pituitary-adrenal (HPA) axis and the production of pro-inflammatory cytokines. Hypercapnia activates the HPA axis, exerts antiinflammatory and antioxidant effects, and can alter the secretion and function of various brain neurotransmitters. There is conflicting evidence surrounding arterial CO(2): its effects on the ischemic brain may be either beneficial or deleterious. Mild hypercapnia may exert some neuroprotection following cerebral ischemia, but severe hypercapnia may aggravate neuronal injury by extra- and intra-cellular acidification and/or impairment of cellular calcium hemostasis. Future studies are required to delineate the potential relationship between arterial CO(2) and prognosis and long-term survival following cerebral ischemia-reperfusion injury. "Therapeutic hypercapnia" seems to be a promising approach to the treatment of stroke patients, and its use should be justified by further experimental and clinical studies.
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PMID:The potential role of carbon dioxide in the neuroimmunoendocrine changes following cerebral ischemia. 1870 31

COPD is a disease that is not confined to the airways and the lungs, but also produces systemic consequences. Muscle weakness is one of these. It is produced by a multitude of factors including deconditioning, systemic inflammation, oxidative stress, nutritional imbalance, reduced anabolic status, systemic corticosteroids, hypoxemia, hypercapnia, electrolyte disturbances, cardiac failure. The most important factors appear to be inactivity and systemic inflammation. Inactivity was shown to be present in patients with COPD from early in the course of the disease on. Systemic inflammation was shown to be predominantly present during COPD exacerbations. IL-6 has the propensity to reduce muscle function in experimental animals. At present there is no evidence of local production of cytokines in the muscle in patients with COPD. Muscle weakness is also important in the clinical course of the disease as it is associated with exercise intolerance, reduced quality of life, enhanced utilization of health care resources and reduced survival. Rehabilitation is the best treatment for muscle weakness and deconditioning in patients with COPD. Indeed, it is the intervention with the largest effect on health status and exercise capacity in these patients. Several factors that may enhance the effects of rehabilitation have been studied. These include: growth hormone/ IGF-I, anabolic steroids, clenbuterol, creatine, anti-cytokine treatment, erythropoietin, oxygen, non-invasive mechanical ventilation and electrical stimulation. Recently, the potential of protease-inhibitors in reversing deconditioning-induced muscle dysfunction was demonstrated. Adjuncts are potentially particularly useful in patients who do not respond to a rehabilitation programme. Analysis of large d-bases demonstrated that about one third of the patients does not respond to rehabilitation. A follow-up study suggests that decline in exercise capacity after a rehabilitation programme is particularly present in these patients and not in the patients with a clear initial response. A better understanding of the factors controlling the response to rehabilitation, may lead to significant advances in this field.
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PMID:Pulmonary rehabilitation 2007: from bench to practice and back. 1898 Jul 25

It is known that carbon dioxide (CO2) pneumoperitoneum induces fetal acidosis in pregnant ewes. Our aim was to determine changes of the levels of maternal and fetal cytokines interleukin-6, interleukin-8, and tumor necrosis factor alpha after CO2 pneumoperitoneum in pregnant ewes. Eight ewes with singleton pregnancies of 120 to 140 days gestation were anesthetized and intubated. Insufflation produced modest but significant maternal arterial hypercapnia (an increase of 10.7 mm Hg; P<0.001) and acidosis (a decrease in mean pH of 0.1.04; P=0.0005). Fetal pCO2 was increased by 15.3 mm Hg on average and pH was decreased by 0.11 U on average immediately after desufflation (both P<0.001). No significant difference was observed in the concentration of cytokine in the maternal or fetal blood samples. These results suggest that respiratory acidosis does not lead to the elevation of cytokines in pregnant ewes and fetuses, which may contribute to premature labor.
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PMID:Maternal and fetal near-term sheep cytokine responses to carbon dioxide pneumoperitoneum. 1939 Feb 81


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