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Query: UMLS:C0036690 (sepsis)
 59,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Group B beta-hemolytic streptococcus (GBS) infection is an important cause of neonatal pneumonia and sepsis. GBS infection is frequently associated with persistent pulmonary hypertension of the newborn. To better understand the early pulmonary hypertension phase of GBS-induced acute lung injury in a conscious animal, we characterized the pulmonary and systemic hemodynamic response of spontaneously breathing, chronically instrumented newborn lambs to injections of heat-killed type Ib GBS, 0.1-9.0 x 10(9) colony forming units. Heat-killed GBS caused marked dose-dependent increases in mean pulmonary arterial pressure and calculated pulmonary vascular resistance, 190 and 370% at the maximum dose, respectively. Similarly, GBS caused dose-dependent increases in mean systemic arterial pressure and systemic vascular resistance (28.5 and 108% at the maximum dose, respectively) and a decrease in cardiac output (33.5%). Arterial oxygen tension worsened at the higher doses. GBS-induced pulmonary hypertension was decreased by two structurally unrelated, putative leukotriene D4 receptor antagonists. Pretreatment with LY171883 blocked GBS-induced pulmonary hypertension by 95%, and WY48,252 attenuated this effect by 27%. Both drugs completely blocked the hemodynamic effects of exogenous leukotriene D4. For comparison, several lambs received bolus injections of live GBS, either alone or after pretreatment with LY171883. The hemodynamic response to live GBS and attenuation of that response by LY171883 were similar to those caused by similar doses of heat-killed GBS. Thus, bolus injections of heat-killed GBS provide a reproducible model of pulmonary hypertension in conscious newborn lambs. In addition, the sulfidopeptide leukotrienes appear to be important mediators of GBS-induced pulmonary hypertension in newborn lambs.
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PMID:Hemodynamic effects of heat-killed group B beta-hemolytic streptococcus in newborn lambs: role of leukotriene D4. 131 29

Oxygen radicals have been implicated in the pathogenesis of acute lung injury associated with clinical and experimental sepsis. With the use of endotoxin infusion as an in vivo model of sepsis we studied the effect of recombinant-human superoxide dismutase (r-hSOD; 4,200 U/mg), an enzyme that catalyzes the dismutation of superoxide anion, on both the physiologic and biochemical lung changes in awake sheep. Sheep (n = 11) were prepared for chronic measurement of pulmonary hemodynamics and lung fluid balance. Paired experiments were performed in seven of the animals in which they received either endotoxin (1 microgram/kg) alone or in combination with r-hSOD in random order. An additional four sheep received r-hSOD without the lipopolysaccharide. Intravenous infusion of r-hSOD (a loading dose of 12,600 U/kg followed by a maintenance dose of 14,700 U/kg/h for 7 h) resulted in substantial SOD activity, measured by electron spin resonance spectrometry, both in plasma and in lung lymph, and attenuated the expected changes in pulmonary arterial pressure and lung lymph flow after administration of endotoxin. When administered without endotoxin, r-hSOD produced no perceptible change in pulmonary hemodynamics and lung fluid balance. These data suggest that superoxide anion plays an important role in endotoxin-induced lung injury in sheep.
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PMID:Recombinant-human superoxide dismutase attenuates endotoxin-induced lung injury in awake sheep. 131 93

Cyclooxygenase inhibition has been proposed as treatment for sepsis-induced acute lung injury. However, the mechanism of protection offered by the cyclooxygenase inhibitor ibuprofen is not well understood. To elucidate this mechanism, the effects of ibuprofen on the neutrophil respiratory burst and alveolar-capillary membrane leak were studied. Anesthetized swine (15 to 25 kg) were intubated and mechanically ventilated (fraction of inspired oxygen, 0.5). Control animals (n = 5) received a sham infusion of 0.9% NaCl, animals with sepsis (n = 10) received a 1-hour infusion of live Pseudomonas aeruginosa (5 x 10(8) colony-forming units/ml at 0.3 ml/20 kg/hr), and treated animals (ibuprofen-treated control animals [n = 4] or ibuprofen-treated animals with sepsis [n = 9]) received ibuprofen (12.5 mg/kg at 0 and 120 minutes). All animals were studied for 300 minutes. Neutrophils were isolated at 0, 60, and 300 minutes. Neutrophil superoxide anion production (O2-) was assessed in a kinetic fashion (in nanomoles per minute) by superoxide dismutase-inhibitable cytochrome C reduction (phorbol myristate acetate stimulation). Bronchoalveolar lavage protein estimation (0 and 300 minutes) and extravascular lung water (double indicator dilution) were performed to assess alveolar-capillary membrane leak. Ibuprofen significantly attenuated sepsis-enhanced maximum neutrophil generation of O2- (6.0 +/- 0.5 nmol/min for animals with sepsis, 300 minutes, vs 4.1 +/- 0.5 nmol/min for ibuprofen-treated animals, with sepsis, 300 minutes; p less than 0.05), indicating an in vivo down-regulatory effect on neutrophil oxidant generation. Ibuprofen also prevented increased airspace bronchoalveolar lavage protein and extravascular lung water accumulation, suggesting a protective effect on the alveolar-capillary membrane. This protective effect of ibuprofen in acute lung injury may be through a decreased neutrophil respiratory burst.
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PMID:The neutrophil respiratory burst and tissue injury in septic acute lung injury: the effect of cyclooxygenase inhibition in swine. 132 Feb 99

Platelet activating factor (PAF) is considered a key mediator in eliciting the immunologic and metabolic consequences of endotoxic shock and sepsis. Release of oxygen-derived radicals is one of the important and relevant actions of PAF. This study examines the direct and priming effects of PAF on superoxide anion release by perfused liver, isolated Kupffer cells and blood neutrophils. One hour after PAF infusion at a dose of 2.2 micrograms/kg body weight a significant amount of superoxide release (0.71 +/- 0.1 nmol/min/g liver) was measured in the perfused liver compared with the control livers (0.2 +/- 0.01). In the in vitro presence of either phorbol ester or opsonized zymosan, superoxide release following PAF treatment in vivo was significantly increased to 1.36 +/- 0.2 and 4.29 +/- 0.36, respectively. The administration of PAF receptor antagonist (SDZ 63-441) almost completely inhibited the release of this radical. Kupffer cells (KC1, KC2, KC3) and blood neutrophils isolated from PAF-treated rats were also primed for increased production when these cells were challenged in vitro by the activator of protein kinase C, opsonin-coated zymosan as well as the chemotactic factors, complement 5a and F-met-leu-phe. PAF added in vitro to the perfused livers, isolated Kupffer cells or neutrophils from normal animals stimulated the release of superoxide with or without the above agonists. The direct stimulatory effect of PAF on superoxide release was inhibited by the PAF receptor antagonist in vitro. The role of PAF in the LPS-induced superoxide release by the perfused liver was also examined by the administration of PAF antagonist in endotoxic rats. The antagonist inhibited the LPS-mediated superoxide release at 1 hr, but not at 3 hr post-treatment. These results indicate that PAF stimulates and primes the hepatic elements to release superoxide. PAF may be an important factor during the early phase of endotoxemia, while other bioactive substances may take over at a later phase. Therefore, PAF is a key mediator that can directly enhance the release of toxic oxygen-derived radicals which may contribute to organ failure during endotoxemia or sepsis.
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PMID:Platelet activating factor stimulates and primes the liver, Kupffer cells and neutrophils to release superoxide anion. 133 36

From previous studies it has been hypothesized that multiple organ failure and high level of mortality, seen in critically ill septic patients, may be due to defective oxygen extraction and tissue hypoxia occurring early in the course of sepsis. Oxygen flux test has been proposed as a method of revealing an occult oxygen debt. We used a one hour dobutamine infusion test, in septic patients, without increase in blood lactate. Fifty patients with sepsis syndrome entered a multicentric prospective study. After fluid loading to increase pulmonary artery occlusion pressure (Paop) to a minimum value of 10 mmHg, all the patients were given 10 mcg/kg.min of dobutamine for one hour. Hemodynamic and metabolic variables were recorded before, HO, and after the test, H1 (cardiac index, Paop, oxygen deliver, DO2, and consumption, VO2, oxygen extraction ratio, (OER), blood lactate). The dobutamine test allowed to identify responders (R) who increased VO2 by more than 15% and non-responders. R and NR differed significantly in mortality (8.5% vs 44.4%). The test has a good predictive value for surviving. Without respect of the result of the test, the patients were randomized in two groups. The group D+ was given conventional therapy and dobutamine at the same rate of infusion for 9 consecutive days and the D- group received only conventional therapy. The RD+ patients improved more rapidly when compared with RD-, NRD+, NRD-. We concluded that a one hour dobutamine test is able to identify R and NR critically ill septic patients. The response is associated with significant difference in outcome.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Relation between oxygen delivery and consumption during septic states. Value of an early dobutamine test]. 134 94

Acute respiratory failure in pregnancy is an important cause of maternal and fetal morbidity and mortality. Causes include: ARDS, venous air embolism, beta-adrenergic tocolytic therapy, asthma, thromboembolic disease, pneumothorax, and pneumomediastinum. The most common predisposing diseases for ARDS complicating pregnancy are sepsis, pneumonia, aspiration of gastric contents, and amniotic fluid embolism. Knowledge of normal maternal-fetal physiology and determinants of fetal oxygen delivery (uterine blood flow, placental transfer, fetal circulation) can help sustain normal fetal development, usually without compromising maternal care. The increased microvascular permeability seen in ARDS is likely mediated by neutrophils, proinflammatory mediators (e.g., tumor necrosis factor, interleukin-1, arachidonic acid metabolites) and activation of the complement cascade. Treatment of respiratory failure in pregnancy is largely supportive, including mechanical ventilation, hemodynamic support, nutrition, and prophylaxis against thromboembolism. No specific therapy has as yet been proven effective for ARDS, other than treating the underlying cause. Respiratory failure from status asthmaticus is treated with vigorous bronchodilator therapy, high-dose glucocorticosteroids, magnesium sulfate, and careful ventilator management. Occasionally, more experimental therapies (e.g., isoproterenol infusion, halothane anesthesia) are indicated. Certain strategies can help prevent respiratory failure from aspiration of gastric contents, beta-adrenergic tocolytic therapy, and thromboembolic disease.
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PMID:Acute respiratory failure in pregnancy. 136 44

Inhibitors of nitric oxide synthase (NOS) have been reported to increase mean arterial pressure in animal models of sepsis and recently have been given to patients in septic shock. However, controlled studies to determine the effects of these agents on cardiovascular function and survival in awake animal models of sepsis have not been reported. To examine the therapeutic potential of NOS inhibition in septic shock, we challenged canines with endotoxin (2 or 4 mg/kg i.v.) and treated them with either normal saline or N omega-amino-L-arginine (10 or 1 mg/kg/h), the most specific inhibitor available for the isoform of NOS implicated in septic shock. Endotoxemic animals treated with N omega-amino-L-arginine (n = 11) had higher systemic and pulmonary vascular resistance indices (SVRI and PVRI, p less than or equal to 0.033) and decreased heart rates (p = 0.009), cardiac indices (CI, p = 0.01), oxygen delivery indices (p = 0.027), and oxygen consumption indices (p = 0.046) compared with controls (n = 6). Moreover, N omega-amino-L-arginine increased mortality rates after endotoxin challenge (10 of 11 vs. 1 of 6 controls, p = 0.005). Administration of L-arginine did not improve survival or alter the cardiopulmonary effects of N omega-amino-L-arginine, which suggests that inhibition of NOS may not have been competitive. In normal animals, N omega-amino-L-arginine alone (n = 3) increased SVRI (p = 0.0008) and mean arterial pressure (p = 0.016), and decreased CI (p = 0.01) compared with saline-treated controls (n = 3), but, at the high dose, also produced neuromuscular rigidity and seizure-like activity that was not apparent in the endotoxemic model. Thus, the mortality rate from endotoxemia increased either because of NOS inhibition per se or because of properties unique to N omega-amino-L-arginine, or both.
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PMID:N omega-amino-L-arginine, an inhibitor of nitric oxide synthase, raises vascular resistance but increases mortality rates in awake canines challenged with endotoxin. 138 77

Tissue oxygenation in the gastrointestinal tract was studied in a porcine model in which septic shock was induced by fecal peritonitis. The oxygen delivered was estimated by measuring the portal venous blood flow and the calculated arterial oxygen saturation. The oxygen consumption of the gut, including the pancreas and spleen, was monitored by measuring the portal venous blood flow and the difference between the calculated arterial oxygen and the measured portal venous oxygen saturation. In addition, the oxygenation of the gut mucosa was followed via the tonometric technique. Furthermore, lactate was measured in arterial and portal blood. The experimental animals were divided into two groups, one control (n = 6) and one experimental (n = 6). Peritonitis was introduced by installation of a standardized amount of autologous feces into the abdominal cavity. The animals were followed for 5 hr. Very early during the course of sepsis there was a fall in gut intramucosal pH (pHi), and this was evident before any reduction in splanchnic DO2. Furthermore, an early increase in splanchnic VO2 was evident simultaneously with the fall in pHi. Arterial pH and lactate were not able to detect the inadequate regional tissue oxygenation. It is concluded that pHi measured with the tonometric technique is sensitive in detecting gut mucosal ischemia, and it is therefore highly likely that tonometry would be a valuable method in monitoring severe ill patients.
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PMID:Early gut ischemia in experimental fecal peritonitis. 139 60

Endotoxin is a major mediator of the life-threatening cardiovascular dysfunction that characterizes Gram-negative sepsis. In animal models of endotoxemia, pretreatment with ibuprofen or pentoxifylline attenuates some of these cardiovascular changes. To evaluate the effects of these agents on the human cardiovascular response to endotoxemia, hemodynamic variables were measured serially in 24 normal subjects who were given intravenous endotoxin. The subjects were randomized to receive oral ibuprofen (n = 9), pentoxifylline (n = 10), or no medication before endotoxin administration (n = 5). The subjects were volume loaded 3-5 h after endotoxin administration, and hemodynamic measurements were reassessed. Core temperature after endotoxin alone or endotoxin-pentoxifylline approached a maximum at 3 h (greater than or equal to 38.6 degrees C), while the endotoxin-ibuprofen group remained afebrile. At 3 and 5 h, all three groups had significant increases in heart rate, cardiac index, oxygen delivery, and oxygen consumption, while systemic vascular resistance index decreased significantly from baseline. The oxygen extraction ratio remained unchanged. After volume loading, the left ventricular ejection fraction and left ventricular end-diastolic and end-systolic volume indexes did not differ among the groups. The hyperdynamic cardiovascular response to endotoxin in humans occurs in the absence of fever and is not significantly ameliorated by oral cyclooxygenase or phosphodiesterase inhibition.
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PMID:Effects of ibuprofen and pentoxifylline on the cardiovascular response of normal humans to endotoxin. 140 57

Under normal conditions the intestinal mucosa is impermeable to potentially harmful materials from the intestinal lumen. Mucosal disruption promotes bacterial translocation, which is postulated to be a fuel source for sepsis and multiorgan failure. We have previously demonstrated that mesenteric ischemia-reperfusion (I/R) injury increases intestinal permeability (IP); however, the mechanism remains unclear. This study was designed to examine the hypothesis that changes in IP, after I/R injury, are mediated by xanthine oxidase-generated, oxygen-derived free radicals. Thirty-three Sprague-Dawley rats (weighing 300 to 400 g) were included in this study. Group 1 (n = 10) received enteral allopurinol, a xanthine oxidase inhibitor, 10 mg/kg daily for 1 week prior to mesenteric ischemia. Group 2 consisted of 11 untreated, ischemic animals. Groups 1 and 2 were subjected to superior mesenteric artery occlusion with interruption of collateral flow for 20 minutes to produce ischemic injury to the intestine. An additional 12 rats (group 3), served as nonischemic controls (sham). A loop of distal ileum was isolated and cannulated proximally and distally to allow luminal perfusion with warmed Ringer's lactate at 1 mL/min. IP was determined in all groups by quantitatively measuring the plasma-to-luminal clearance of chromium (51Cr)-labeled ethylenediaminetetraacetate (EDTA) at baseline, during ischemia and 20, 40, and 60 minutes after reperfusion. Complete ischemia produced significant increases in IP over baseline values in the untreated rats (group 2, baseline: 0.49 +/- 0.006, ischemia: 0.149 +/- 0.039) compared with sham rats (baseline: 0.41 +/- 0.006; ischemia: 0.047 +/- 0.009) or allopurinol-treated rats (baseline: 0.098 +/- 0.020, ischemia: 0.073 +/- 0.012, P less than .001).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Allopurinol prevents intestinal permeability changes after ischemia-reperfusion injury. 140 60


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