Reduction of oedema formation after preconditioning with dopamine in an isolated rat lung model is mediated by adrenergic receptors.

BACKGROUND: Donor treatment with dopamine (DA) is an effective modality to improve organ quality by reduction of hypothermic, ischemic and reperfusion (I/R) injury. It is unknown by which mechanism DA reduces oedema formation and inflammation. Therefore we tested the first time in an isolated rat lung model if dopaminergic or adrenergic receptors are involved. MATERIAL/METHODS: Rats were treated for 1 hr with NaCl, DA or simultaneously with DA alpha- beta- D1- or D2-receptor blockers. Thereafter lungs were explanted, flushed with Perfadex-solution and stored at 4°C. Peak inspiratory pressure (PIP), pulmonary arterial pressure (PAP) and lung weight were measured during reperfusion of 3 hrs. Inflammatory mediators and the expression of adhesion molecules were measured after perfusion. RESULTS: Up to 6 hours of hypothermia did not influence oedema formation or PIP and PAP during reperfusion time. However, hypothermia after 8 hrs significantly increased PIP, PAP and pulmonary oedema in NaCl, alpha- and beta-blocker treated lungs, but significantly not in DA, D1- or D2-blocker treated lungs. Perfusion and ventilation alone induced a strong upregulation of cytokine-induced neutrophil chemoattractant-1 and adhesion molecules in untreated, alpha- and beta-blocker treated lungs, while in DA, D1- and D2-blocker treated lungs significant lower levels were found. CONCLUSIONS: Our study suggests that dopamine mediated protective effects on I/R damage and inflammation in donor lungs are most likely mediated via adrenergic receptors. These findings are highly relevant because new strategies for organ preservation are necessary in terms of long donation waiting lists.

Pain ratings and somatosensory evoked responses to repetitive intramuscular and intracutaneous stimulation in fibromyalgia syndrome.

To determine the presence of perceptual sensitization and related brain responses we examined 15 patients with fibromyalgia syndrome and 15 healthy controls comparable in age and sex. Multichannel EEG recordings and pain ratings were obtained during the presentation of 800 painful electrical intramuscular and intracutaneous stimuli to the left m. erector spinae and the left m. extensor digitorum. The stimulus intensity was adjusted to 50% between pain threshold and tolerance. Detection and pain thresholds were significantly lower in the fibromyalgia syndrome group. Sensitization occurred for both groups during intramuscular stimulation. In the EEG data the fibromyalgia syndrome patients showed higher N80 amplitudes compared with the healthy controls. Arm stimulation and intramuscular stimulation yielded higher N80 and N150 amplitudes compared with intracutaneous stimulation or stimulation of the back. These results indicate lower pain thresholds in the fibromyalgia syndrome patients after electrical stimulation and a higher N80 amplitude both indicative of enhanced sensory processing in this group.

Donor dopamine treatment limits pulmonary oedema and inflammation in lung allografts subjected to prolonged hypothermia.

BACKGROUND: Endothelial barrier dysfunction severely compromises organ function after reperfusion. Because dopamine pretreatment improves hypothermia mediated barrier dysfunction, we tested the hypothesis that dopamine treatment of lung allografts positively affects tissue damage associated with hypothermic preservation and reperfusion. METHODS: Rats were treated for 1 hr with dopamine (5 microg/min/kg) or vehicle (NaCl). Thereafter lungs were explanted, flushed with Perfadex solution and stored at 4 degrees C for different time periods. Peak inspiratory pressure (PIP), pulmonary arterial pressure (PAP), and lung weight were measured online during reperfusion. Inflammatory mediators in the perfusate and the expression of adhesion molecules in situ were measured after perfusion. RESULTS: Lungs could tolerate a cold ischemia time of up to 6 hr with stable PIP, PAP, and no edema formation upon reperfusion. Cold ischemia time above 6 hr significantly increased PIP, PAP, and pulmonary edema in untreated but not in dopamine treated lungs (P< or =0.001 dopamine treated vs. untreated). Perfusion and ventilation alone induced a strong up-regulation of cytokine-induced neutrophil chemoattractant-1 and adhesion molecules in untreated lungs, whereas in dopamine treated lungs significantly lower levels were found. Dopamine treatment also inhibited tissue damage associated with hypothermic preservation as measured by nicotinamide adenine dinucleotide staining. CONCLUSION: Our study suggests that donor dopamine treatment is a highly effective modality to maintain organ quality of lung allograft. These findings are of high clinical relevance because prevention of tissue damage might reduce complications associated with lung transplantation and hence improve graft survival in lung transplant recipients.

Increased circulating endothelial progenitor cells in septic patients: correlation with survival.

OBJECTIVE: Endothelial damage and detachment of endothelial cells are known to occur in septic patients. Thus, recruitment of circulating endothelial progenitor cells (cEPCs) to these lesions might have a beneficial effect on the clinical course in septic patients. Therefore, we were interested in whether EPCs, detected by flow cytometry, are increasingly mobilized during sepsis and if this mobilization is associated with clinical outcome. DESIGN: Prospective, nonrandomized study. SETTING: Intensive care unit of a university hospital. PATIENTS: Patients with (n = 32) and without (n = 15) sepsis and healthy volunteers (n = 15). INTERVENTIONS: Peripheral blood mononuclear cells were isolated by Ficoll density gradient centrifugation, and cEPCs were characterized by three-color fluorescence flow cytometry using antibodies against CD133, CD34, and vascular endothelial growth factor receptor-2. Serum concentrations of vascular endothelial growth factor, granulocyte macrophage-colony stimulating factor, and erythropoietin were determined by enzyme-linked immunosorbent assay. Severity of sepsis was assessed according to Acute Physiology and Chronic Health Evaluation II scoring. MEASUREMENTS AND MAIN RESULTS: In septic patients, the number of cEPCs was significantly higher than in nonseptic intensive care unit patients (p < .05) and healthy controls (p < .02). Nonsurvivors (n = 8), defined as death within 28 days after onset of sepsis, had significantly lower numbers of cEPCs than survivors (n = 24) (p < .0001). The number of cEPCs was correlated with survival in septic patients. Serum vascular endothelial growth factor concentrations were significantly higher in septic patients compared with nonseptic intensive care unit patients and healthy controls (p < .01) and correlated with the cEPC numbers (p < .0001). Similar findings were observed for granulocyte macrophage-colony stimulating factor and erythropoietin. CONCLUSIONS: Our data suggest that cEPC enumeration in peripheral blood of septic patients might be a valuable marker to assess the clinical outcome in these patients.

Central processing of acute muscle pain in chronic low back pain patients: an EEG mapping study.

The presence of perceptual sensitization and related brain responses was examined in 14 chronic low back pain (CLBP) patients and 13 healthy controls comparable in age and sex. Multichannel EEG recordings and pain ratings were obtained during the presentation of 800 painful electrical intramuscular and intracutaneous stimuli each to the left m. erector spinae and the left m. extensor digitorum. Perception and pain thresholds were not significantly different between the two groups, though patients showed significantly more perceptual sensitization. Across all stimulation conditions, a larger EEG component 80 milliseconds after stimulation was observed in the CLBP group. No significant group differences were found for the N150. The component 260 milliseconds after stimulus onset was significantly smaller in the CLBP group. N80, N150, and perceptual sensitization were significantly positively correlated. These results indicate enhanced perceptual sensitization and enhanced processing of the sensory-discriminative aspect of pain, as expressed in the N80 component, in CLBP patients. This may be one neurophysiologic basis of sensitization and the chronicity process. The lower P260 component in the patients may be explained in terms of tonic pain inhibiting phasic pain or may be related to the affective distress observed in this patient group.

Clinical review: immunomodulatory effects of dopamine in general inflammation.

Large quantitaties of inflammatory mediators are released during the course of endotoxaemia. These mediators in turn can stimulate the sympathetic nervous system (SNS) to release catecholamines, which ultimately regulate inflammation-associated impairment in tissue perfusion, myocardial impairment and vasodilatation. Treatment of sepsis is based on surgical and/or antibiotic therapy, appropriate fluid management and application of vasoactive catecholamines. With respect to the latter, discussions on the vasopressor of choice are still ongoing. Over the past decade dopamine has been considered the 'first line' vasopressor and is frequently used to improve organ perfusion and blood pressure. However, there is a growing body of evidence that dopamine has deleterious side effects; therefore, its clinical relevance seems to be more and more questionable. Nevertheless, it has not been convincingly demonstrated that other catecholamines are superior to dopamine in this respect. Apart from its haemodynamic action, dopamine can modulate immune responses by influencing the cytokine network. This leads to inhibition of expression of adhesion molecules, inhibition of cytokine and chemokine production, inhibition of neutrophil chemotaxis and disturbed T-cell proliferation. In the present review we summarize our knowledge of the immunomodulatory effects of dopamine, with an emphasis on the mechanisms by which these effects are mediated.

Regional heterogeneity of cerebral blood flow response to graded pressure-controlled hemorrhage.

BACKGROUND: Little is known about the regional distribution of cerebral blood flow (CBF) in nonanesthetized animals during periods of lowered blood pressure. The present investigation addresses the specific reaction patterns of local cerebral blood flow (LCBF) in comparison with mean CBF during graded pressure-controlled hemorrhagic shock in conscious rats. METHODS: Conscious rats were subjected to graded pressure-controlled hemorrhage (to 85, 70, 55, or 40 mm Hg) by arterial blood withdrawal. After a period of 30 minutes, blood pressure was stabilized by withdrawal or reinfusion of blood. LCBF was determined autoradiographically by the iodo(14C)antipyrine method in 34 brain structures, and mean CBF was calculated and compared with the values of nonhemorrhaged control animals. RESULTS: Mean CBF remained unchanged except for the group with the lowest blood pressure of 40 mm Hg (decrease in CBF of 28%). Otherwise, LCBF was increased in some brain structures at an unchanged mean CBF. Congruently, at 40 mm Hg, the decrease in mean CBF did not show up in all brain structures, the local pattern of CBF varying between an unchanged and a profoundly decreased CBF. The mean coefficient of variation of CBF was increased with the severity of hemorrhagic shock, which indicates an enhanced heterogeneity of CBF. CONCLUSION: Because of the substantial heterogeneity in the responses of LCBF to pressure-controlled hemorrhage, autoregulation of CBF during pressure-controlled hemorrhagic shock has to be reconsidered on a regional basis.

Blood loss from laboratory tests.

BACKGROUND: Laboratory tests can be an important source of blood loss in hospitals, especially for newborns and patients in intensive care. The aim of this study was to quantify blood loss for laboratory diagnostic tests in a large number of patients in a teaching hospital. METHODS: We estimated blood loss by multiplying the number and volumes of sampling tubes collected from 2654 adult inpatients. We compared the number of tests per patient for all inpatients and intensive care unit patients during the first period and again in the same time period 1 year later when cumulative blood-loss volumes were being reported to physicians and educational information had been given to decrease blood loss from laboratory tests. RESULTS: For 95% of the patients, blood loss during hospitalization was <196 mL. The largest proportion of the blood samples was used for clinical chemical tests (median, 45%), followed by hematologic (median, 26%) and coagulation (median, 17%) tests. In the surgical and cardiovascular surgical intensive care units, however, blood gas analyses accounted for 19-34% (medians) of the use. For 5% of the patients, all undergoing intensive care, blood loss was >200 mL and for 0.7% was >600 mL during their hospital stay. Such high blood losses were observed in patients with long-term ventilation, coagulation disorders, and repeated surgery. The largest median blood loss was in patients undergoing cardiovascular surgery (median, 201 mL). The mean number of tests was 44 per inpatient before cumulative blood loss was being reported and 46 when it was being reported. CONCLUSIONS: Blood loss from laboratory diagnostic testing is not likely to pose a problem for most hospitalized patients. Blood loss is greater in intensive care patients and after cardiovascular surgical procedures. Reporting of the cumulative individual blood loss did not decrease blood loss for laboratory testing.

Amelioration of endotoxin-induced sepsis in rats by membrane anchored lipid conjugates.

OBJECTIVE: In the pathogenesis of septic shock, caused by either bacterial toxins or trauma, increased production of multiple proinflammatory mediators, such as phospholipase A(2) (PLA(2)), cytokines, and chemokines, is known to be of major importance. The present study was undertaken to investigate the influence of a newly designed extracellular PLA(2) inhibitor (ExPLI) on synthesis of proinflammatory mediators and mortality rate in a rat sepsis model. DESIGN: Prospective, randomized animal study. SETTING: Experimental laboratory. SUBJECTS: Male Wistar-rats weighing 200-300 g. INTERVENTIONS: Mortality was induced by intraperitoneal bolus administration of lipopolysaccharide 15 mg/kg in 22 rats that were pretreated with NaCl or ExPLI (150 mg/kg). Furthermore, nine rats received a sublethal bolus of lipopolysaccharide (7.5 mg/kg) and nine rats received lipotechoic acid (8 mg/kg) simultaneously with or after ExPLI administration. Blood samples were collected from these rats, and cytokine concentrations were assessed by enzyme-linked immunosorbent assay. Lung and kidney were removed for RNA isolation and immunohistological analysis. MEASUREMENTS AND MAIN RESULTS: ExPLI treatment significantly reduced lipopolysaccharide-induced mortality of rats (90.9 and 36.4%, p <.05). Up-regulation of tumor necrosis factor-alpha and interleukin-6 production in serum after endotoxin treatment was significantly inhibited when ExPLIs were administered at the time of or before sepsis induction by using lipopolysaccharide or lipotechoic acid (p <.01). Similarly, messenger RNA expression of secreted PLA(2)-IIA, interleukin-1, or inducible nitric oxide synthase and the expression of intercellular adhesion molecule-1 were significantly down-regulated in lung and kidney of ExPLI-treated rats, as demonstrated by RNase protection assay, reverse transcription-polymerase chain reaction, or immunohistochemistry. CONCLUSIONS: ExPLIs may be considered as potentially effective compounds to prevent the production of inflammatory mediators and to improve mortality rate in septic patients.

Secreted phospholipases A2 induce the expression of chemokines in microvascular endothelium.

Acute respiratory distress syndrome (ARDS) is characterized by alterations in microvascular permeability. In ARDS secreted phospholipase A(2) (sPLA(2)) IB and IIA are found to be highly upregulated. In this study, we therefore investigated the influence of exogenously added sPLA(2)-IB and sPLA(2)-IIA on the production of chemokines and adhesion molecules in lung microvascular endothelial cells (LMVEC). Treatment of LMVEC with sPLA(2)s resulted in a significant increase in the production of chemokines and adhesion molecules due to an increased expression of their mRNA and in an enhanced release of oleic acid. The upregulation of chemokines and adhesion molecules by LPS was stronger in the presence of sPLA(2). Activation of NF-kappaB occurred upon stimulation with sPLA(2). Moreover the MAPkinase pERK seems to be involved since a specific pERK inhibitor, e.g., U0126, but not a p38Kinase inhibitor, e.g., SB203580 prevented sPLA(2)-induced chemokine upregulation. Our data therefore suggest that LMVEC are a highly sensitive target for the direct action of extracellular sPLA(2)s.

Hypertonic-hyperoncotic solutions reduce the release of cardiac troponin I and s-100 after successful cardiopulmonary resuscitation in pigs.

UNLABELLED: In some patients, cardiopulmonary resuscitation (CPR) can revive spontaneous circulation (ROSC). However, neurological outcome often remains poor. Hypertonic-hyperoncotic solutions (HHS) have been shown to improve microvascular conductivity after regional and global ischemia. We investigated the effect of infusion of HHS in a porcine CPR model. Cardiac arrest was induced by ventricular fibrillation. Advanced cardiac life support was begun after 4 min of nonintervention and 1 min of basic life support. Upon ROSC, the animals randomly received 125 mL of either normal saline (placebo, n = 8) or 7.2% NaCl and 10% hydroxyethyl starch 200,000/0.5 (HHS, n = 7). Myocardial and cerebral damage were assessed by serum concentrations of cardiac troponin I and astroglial protein S-100, respectively, up to 240 min after ROSC. In all animals, the levels of cardiac troponin I and S-100 increased after ROSC (P < 0.01). This increase was significantly blunted in animals that received HHS instead of placebo. The use of HHS in the setting of CPR may provide a new option in reducing cell damage in postischemic myocardial and cerebral tissues. IMPLICATIONS: Infusion of hypertonic-hyperoncotic solutions (HHS) after successful cardiopulmonary resuscitation in pigs significantly reduced the release of cardiac troponin I and cerebral protein S-100, which are sensitive and specific markers of cell damage. Treatment with HHS may provide a new option to improve the outcome of cardiopulmonary resuscitation.

Improvement in stroke quality management by an educational programme.

Time after symptom onset in ischaemic stroke has to be as short as possible to increase success of treatment. We prospectively analysed latencies from symptom onset until the start of therapy and the rate of thrombolysis in 196 patients with suspected stroke sequentially admitted to the hospital before (6 weeks prior, n = 83) and after (n = 113) initiating an educational stroke programme (EP). A total of 345 dispatchers, paramedics, and emergency staff were trained, each person for at least 2 h. The mean pre-hospital time interval from symptom onset until admission was significantly decreased by nearly 2 h (p < 0.05). Thrombolytic therapy frequencies increased from 2 to 10.5% (p < 0.01) because the overall mean time interval from admission to the start of therapy significantly decreased (p < 0.01) by 69 min after the EP, with increasing numbers of patients suitable for acute stroke therapies within a 0- to 3-hour treatment window.