Biomedical subjects

U B Brückner

Publications and source records attributed to U B Brückner.

At least 19 recordsLinked to original sources

PubMed2004

Systemic inflammatory response after endoscopic (TEP) vs Shouldice groin hernia repair.

Endoscopic techniques are commonly used for many different types of surgery. It is claimed that videoendoscopic procedures have the advantage of being less traumatic and of offering higher postoperative patient comfort than conventional open techniques. The extent of tissue trauma can be evaluated on the basis of the inflammatory response observed in the wake of surgery. Available studies that have compared endoscopic and conventional techniques suggest that endoscopic cholecystectomy, laparoscopic colorectal resection, and thoracoscopic pulmonary resection have immunologic advantages over conventional approaches. The objective of this prospective study was to determine whether endoscopic hernia repair techniques are also preferable to conventional procedures and to what extent the anesthetic technique (local or general anesthesia) influences the postoperative inflammatory response. For this purpose, biochemical monitoring of cytokine activity [C-reactive protein (CRP), prostaglandin F1alpha (PGF1alpha), neopterin, interleukin-6 (IL-6)] was done prospectively in 101 patients [totally extraperitoneal approach (TEP) n=32, unilateral n=12, bilateral n=20; Shouldice n=69, local anesthesia (LA) n=23, general anesthesia (GA) n=46] before and until 3 days after surgery. The parameters IL-6 and PGF1alpha suggested that the immune trauma immediately after surgery was significantly higher in the group of patients with endoscopic hernia repair than in the group of patients who received a Shouldice repair. No significant differences were observed after the first postoperative day. A comparison between the TEP group and the patients who received conventional surgery under local anesthesia showed that the TEP approach was also associated with a higher postoperative neopterin level. Within the first 3 days after surgical intervention, bilateral endoscopic hernia repair induced no significantly higher inflammatory response than the surgical treatment of unilateral conditions. The anesthetic procedure that was used in the Shouldice operation had no significant effect on inflammatory response. Unlike other types of endoscopic surgery, the repair of groin hernias using an endoscopic technique cannot be regarded as a minimally invasive procedure that is less traumatic than conventional approaches. Instead, the conventional Shouldice procedure appears to cause the lowest inflammatory response and to be the least traumatic approach to hernia repair, especially when it is performed under local anesthesia.

Adolescent↗

PubMed2001

[New methods in polytrauma surgery. Results of a Study Congress at castle Reisenburg 27/28 February 2000].

Recently, in Germany the academic environment has changed and an upheaval occurred that directly do affect academic research activities. Increasingly, the funding of scientific projects is not provided anymore by the universities themselves or the government, but has to be acquired as grants. While in the past, research was conducted by single departments, nowadays and more and more in the future scientific networks have to be established by combining 'local' and even 'distant' knowledge. With this changing background in mind representatives of different scientific institutions met at the Reisensburg castle to discuss the current state and future trends in four major research fields: "Epidemiology of Severe Trauma", "Head Injury", "Pathophysiology of Damage to the Chest", and "Posttraumatic Soft Tissue Injury".

Germany↗

PubMed2001

Hepatic oxygen exchange and energy metabolism in hyperdynamic porcine endotoxemia: effects of the combined thromboxane receptor antagonist and synthase inhibitor DTTX30.

OBJECTIVE: We compared the effects of thromboxane receptor antagonist and synthase inhibitor DTTX30 on systemic and liver blood flow, oxygen (O2) exchange and energy metabolism during 24 h of hyperdynamic endotoxemia with untreated endotoxemia. DESIGN: Prospective, randomized, experimental study with repeated measures. SETTING: Investigational animal laboratory. SUBJECTS: Twenty-seven domestic pigs: 16 during endotoxemia with volume resuscitation alone; 11 with endotoxemia, volume resuscitation and treatment with DTTX30. INTERVENTIONS: Continuous infusion of Escherichia coli lipopolysaccharide (LPS) for 24 h together with volume resuscitation. After 12 h of endotoxemia, DTTX30 was administered as a bolus of 0.12 mg kg-1 followed by 12 h continuous infusion of 0.29 mg kg-1 per h. MEASUREMENTS AND RESULTS: DTTX30 effectively counteracted the endotoxin-associated increase in TXB2 levels and increased 6-keto-PGF1 alpha with a significant shift of the thromboxane/prostacyclin ratio towards predominance of prostacyclin. DTTX30 prevented the significant progressive endotoxin-induced decrease of mean arterial pressure (MAP) below baseline while maintaining cardiac output (CO), and increased the fractional contribution of liver blood flow to CO without an effect on either hepatic O2 delivery or O2 uptake. The mean capillary hemoglobin O2 saturation (HbO2) on the liver surface and HbO2 frequency distributions remained unchanged as well. CONCLUSIONS: DTTX30 significantly attenuated the endotoxin-induced derangements of cellular energy metabolism as reflected by the diminished progressive decrease in hepatic lactate uptake rate and a blunted increase in hepatic venous lactate/pyruvate ratios. While endotoxin significantly increased the endogenous glucose production (EGP) rate, EGP returned towards baseline levels in the DTTX30-treated group. Thus, in our model DTTX30 resulted in hemodynamic stabilization concomitant with improved hepatic metabolic performance.

Animals↗

PubMed2001

Early inflammatory mediator response following isolated traumatic brain injury and other major trauma in humans.

The inflammatory response following isolated traumatic brain injury (TBI) is characterised by the release of pro- and anti-inflammatory mediators. In order to determine the important mediators regarding survival and outcome of patients with severe traumatic isolated head injuries, we performed this prospective preclinical and clinical study starting upon arrival at the site of the accident. After approval by the local ethics board committee, 94 multiple-injury patients were enrolled. Of these, 72 patients suffered from major injuries; the other 22 patients had a severe isolated brain injury and were allotted to subsets of survival or nonsurvival. Of the pro- and anti-inflammatory mediators (cytokines, arachidonic acid metabolites and soluble adhesion molecules), interleukin-6 (IL-6), IL-12 and malone dialdehyde (MDA) appeared to be of specific importance; maximum IL-6 plasma levels were eightfold higher in cases of nonsurvival than in those of survival. Patients that did not survive TBI were the only ones to express an IL-12 increase, whereas survivors and patients with other major trauma did not show any increase within the first 24 h. An early distinct decrease of MDA showed in patients who did not survive TBI, in contrast to survivor patients who exposed almost constant levels during the first 24 h.

Adult↗

PubMed2001

Trauma severity-dependent changes in AT III activity.

Trauma may cause a relevant reduction in antithrombin (AT) III activity, which is associated with adverse events. The very early changes in AT III activity after accident trauma are still unclear and possible relations with Interleukin (IL)-6, which is known to interact with AT III, have not been investigated so far. Upon approval of the IRB/IEC, 30 patients were enrolled with multiple injuries (ISS 9-75). Groups were performed according to injury severity, IL-6 concentration, and survivors versus non-survivors. Blood samples were collected at the scene of accident then at 2, 4, 6, 12, and 24 h and at day 3, 5, 10 and 15. No patient received AT III concentrates. In all groups a reduction in AT III activity occurred, which was most pronounced in very severe injuries. The activity re-increased spontaneously and steadily in all groups regardless of the IL-6 concentration. There was no clear impact of the AT III activity on survival.

Adolescent↗

PubMed2000

Is interleukin 6 an early marker of injury severity following major trauma in humans?

HYPOTHESIS: Interleukin 6 (IL-6), a multifunctional cytokine, is expressed by various cells after many stimuli and underlies complex regulatory control mechanisms. Following major trauma, IL-6 release correlates with injury severity, complications, and mortality. The IL-6 response to injury is supposed to be uniquely consistent and related to injury severity. Therefore, we designed a prospective study starting as early as at the scene of the unintentional injury, to determine the trauma-related release of plasma IL-6 in multiple injured patients. PATIENTS AND METHODS: On approval of the local ethics committee, 94 patients were enrolled with different injuries following trauma (Injury Severity Score [ISS] median, 19; range, 3-75). The patients were rescued by a medical helicopter. Subsets were performed according to the severity of trauma--4 groups (ISS, <9, 9-17, 18-30, and >32)-and survival vs nonsurvival. The first blood sample was collected at the scene of the unintentional injury before cardiopulmonary resuscitation, when appropriate. Then, blood samples were collected in hourly to daily intervals. Interleukin 6 plasma levels were determined using a commercial enzyme-linked immunosorbent assay test. The short-term phase protein, C-reactive protein, was measured to characterize the extent of trauma and to relate these results to IL-6 release. RESULTS: As early as immediately after trauma, elevated IL-6 plasma levels occurred. This phenomenon was pronounced in patients with major trauma (ISS, >32). Patients with minor injury had elevated concentrations as well but to a far lesser extent. In surviving patients, IL-6 release correlated with the ISS values best during the first 6 hours after hospital admission. All patients revealed increased C-reactive protein levels within 12 hours following trauma, reflecting the individual injury severity. This was most pronounced in patients with the most severe (ISS, >32) trauma. CONCLUSIONS: To our knowledge, this is the first study that elucidates the changes in the IL-6 concentrations following major trauma in humans as early as at the scene of the unintentional injury. The results reveal an early increase of IL-6 immediately after trauma. Moreover, patients with the most severe injuries had the highest IL-6 plasma levels. There is strong evidence that systemic IL-6 plasma concentrations correlate with ISS values at hospital admission. Therefore, IL-6 release can be used to evaluate the impact of injury early regardless of the injury pattern.

Adolescent↗

PubMed2000

Volume replacement in trauma patients within the first 24 h and its impact on the interpretation of biochemical data.

BACKGROUND AND AIMS: Patients of the same and particularly of different trauma studies are primarily incomparable due to different volume replacements. The aim of this prospective study was to analyze the amount of initially administered fluids in trauma patients during the first 24 h and to estimate the impact of dilution on plasma protein concentrations (PPCs) of prostanoids. These substances are vascular endothelium-derived and are thus influenced by blood pressure. PATIENTS/METHODS: Sixty-nine casualties suffering from multiple injuries were enrolled in the study. The amount of any fluid administered was scrutinized during the first 24 h. Patients were divided into subsets according to trauma severity by Injury Severity Score (ISS) (group=G-I: < or = 9; G-II: 10-18; G-III: 19-32; G-IV: >32) and between survivors and non-survivors. At corresponding time points, hemoglobin, hematocrit (Hct) and PPC as well as prostaglandins (PGI, TxA, PGF2a) were evaluated at the site of accident, at hospital admission, and every hour thereafter for the first 24 h. RESULTS: During this period, the total amount of infused fluids ranged between 0.51 (G-I) and >481 (G-IV). The higher the trauma severity, the greater the volume infused (G-III/IV P=0.0003 vs G-I/II). Simultaneously, PPC dropped markedly (P<0.01). Patients who died within 36 h required higher volumes (P<0.003) than survivors. PPC was linearly related (r2=.6685, P<0.001) to Hct. During the first 24 h, the time course of prostanoid concentration was altered when dilution is not taken into account. CONCLUSION: PPC proved a suitable parameter to estimate dilution effects and to adjust plasma concentrations of prostanoids. We recommend that consideration be given to possible dilution effects during the first 24 h when interpreting biochemical data in trauma patients.

Adult↗

PubMed2000

Effects of the combined thromboxane receptor antagonist and synthase inhibitor DTTX-30 on intestinal O2-exchange and energy metabolism during hyperdynamic porcine endotoxemia.

Sepsis may lead to deranged thromboxane-prostacyclin ratio with consecutive organ dysfunction. Because of the suggested role of the gut in the pathogenesis of septic shock and multiple organ failure, we investigated the effects of the novel dual thromboxane synthase inhibitor and receptor antagonist DTTX-30 (TRASI) on intestinal tissue perfusion, O2 kinetics, and energy metabolism over 24 h of hyperdynamic, normotensive porcine endotoxemia. Before, 12, 18, and 24 h after starting continuous i.v. endotoxin (LPS), we measured portal venous (PV) blood flow, intestinal oxygen extraction (iO2ER), intracapillary hemoglobin O2 saturation (HbO2%) of the ileal wall, intramucosal ileal PCO2, PV lactate-pyruvate (L-P) ratio, and plasma levels of thromboxane and prostacyclin. Treatment with TRASI (0.12 mg/kg i.v. bolus injection followed by an infusion of 0.29 mg/kg/h) initiated after 12 h of LPS infusion markedly reduced the plasma thromboxane levels and attenuated the LPS-induced fall in systemic vascular resistance, resulting in hemodynamic stabilization. TRASI did not influence the LPS-induced increase in PV blood flow nor intracapillary HbO2%, thus reflecting unchanged microcirculatory O2 availability and decreased iO2ER, possibly because of reduced O2 requirements. Nevertheless, TRASI prevented the LPS-induced increase in the PV L-P ratio, attenuated the progression of the ileal mucosal-arterial PCO2 gap, and tended to attenuate the gradual fall of PV pH. Hence, compounds like TRASI may beneficially influence LPS-related derangements of gut energy metabolism.

Animals↗

PubMed1999

Early biochemical characterization of soft-tissue trauma and fracture trauma.

OBJECTIVE: The long-term outcome of trauma patients basically depends on the relation between the clearance capacity of the organism, e.g., the lungs, and the antigenic (inflammatory) load in relation to the amount of damaged and perfused tissue. It is necessary to determine quality and quantity of fracture and soft-tissue damage by clinical means as early as possible. It is unknown whether biochemical markers and the impact of soft-tissue trauma correlate and whether there is a predictive value on clinical outcome. METHODS: A total of 107 trauma patients were prospectively enrolled in the study. Blood samples were collected immediately at the site of accident, at hospital admission, and every 2 hours for an interval of 24 hours, then daily. In addition to the biochemical analysis of 20 different substances, the following data were collected and correlated to the laboratory results: Injury Severity Score, polytrauma score of Hannover, modified fracture index, and soft-tissue index. These primary clinical findings as well as the laboratory data were correlated to criteria of clinical outcome such as length of stay in the intensive care unit, length of hospital stay, infections, systemic inflammatory response syndrome, sepsis, multiple organ failure score according to Goris, and finally to primary (< 72 hours), secondary (> 72 hours), and overall lethality. The determination of individual extent and severity of soft-tissue trauma is based on standard partial body volumes derived from healthy volunteers. In addition, clinical estimation of the degree of soft-tissue damage according to the usual classifications was performed. RESULTS: Significant (p > 0.05) correlations were found between fracture as well as soft-tissue trauma and intensive care unit stay, hospital stay, infections, systemic inflammatory response syndrome, multiple organ failure score, serum concentrations/activities of serum interleukin-6 and -8 and creatine kinase during the first 24 hours after trauma. Severe soft-tissue trauma was related to secondary lethality, however, without statistical significance. CONCLUSION: The amount of fracture and soft-tissue damage can be estimated early by analysis of serum interleukin-6 and creatine kinase and is of great importance with regard to long-term outcome after trauma.

Adolescent↗

PubMed1999

[Prostanoid release and lipid peroxidation in patients with thoracic trauma].

UNLABELLED: There is compelling data from recent clinical studies on the impact of damage to the lung on the fate of traumatized patients. The lung reacts with a tremendous release of inflammatory mediators, but, on the other hand, this organ's ability in inactivating those factors is simultaneously attenuated. What is more, it is well known, that there often are no clinical signs of pulmonary dysfunction despite severe lung injury in the early posttraumatic phase. Therefore, in this prospective clinical study the following questions were addressed: (i) Is there any difference of the patients' lung response whether or not the (poly)trauma is associated with damage to the chest, (ii) either in the early or the late posttraumatic phase, and (iii) is there any marker that may prove to be a (significant) predictor of poor overall outcome? METHODS: Upon approval of the local IRB/EC, 35 patients (pts) were enrolled who suffered from multiple injuries. The first blood samples were drawn at admission, then every two hours and in daily intervals. The plasma concentrations of following mediators were analyzed: prostanoids (PGI2, TxA2, PGE2, PGF2 alpha) and products of O2-radicals (malondialdehyde, conjugated dienes). All values were calculated on the basis of the actual plasma protein content to eliminate fluid-induced dilution effects. Subsets of pts were performed according to the different injury pattern: (i) pre-dominantly thoracic trauma (TX, n = 9); (ii) polytrauma with (PTX, n = 19), and (iii) without (PT, n = 7) damage to the lung. RESULTS: As early as at admission, all pts revealed a severity-independent increase (p < 0.01) in most mediators' plasma levels. The pattern-related inflammatory response was most pronounced in casualties who had experienced thoracic trauma irrespective of whether it was combined with polytrauma. Within 1 to 3 days, the plasma levels of most mediators but PGE2 and MDA (all pts) as well as PGF2 alpha (PTX-group) normalized. The reactions of the lipid peroxidation products admitted of no group-differences. CONCLUSIONS: Although there was a pattern-related release of (most) prostanoids which was rather pronounced in polytrauma associated with damage to the lung, we failed in proving any predictive marker to specifically estimate outcome, so far.

Adolescent↗

PubMed1999

[Prognostic importance of preclinically evaluated biochemical mediators in polytrauma].

UNLABELLED: There is compelling data from several clinical studies on the impact of various anti- and proinflammatory mediators on traumatized patients. Immediate trauma-related results, however, are only available from animal experiments so far. Therefore, in this prospective clinical study the following questions were addressed: (I) Is there any marker in the preclinical phase that give information independent of and better than conventional studies conducted so far, (II) does this possible factor prove to be a (significant) predictor of late complications and/or poor overall outcome, and (III) does this mediator provide information that can alter treatment decisions? METHODS: Upon approval of the local IRB/IEC, 85 patients (pts) were enrolled who suffered from multiple injuries. The pts were rescued by the helicopter-based service of the German Army Hospital in Ulm. The first blood samples were drawn at the site of accident and at admission, then in hourly to daily intervals. The plasma concentrations of following mediators were analyzed: Prostanoids, products of O2-radicals, soluble adhesion molecules, various cytokines, C-reactive protein, creatinine kinase, and neopterin. All values were calculated in relation to the actual plasma protein content to eliminate fluid-induced dilution effects. Subsets of patients were performed according to the severity of trauma (ISS < 9; 9-17; 18-31; > 32), based on the different injury pattern, and survivors versus nonsurvivors as well. RESULTS: As early as at the scene of accident, all patients revealed a severity-dependent increase in most mediators' plasma levels. There was, however, also a pattern-related inflammatory response that was most pronounced in pts who had suffered from thoracic trauma irrespective of whether it was associated with multiple trauma. In a total, 15 pts died within 72 h after the accident. In those casualties, the plasma concentrations of prostaglandin E2 (P < 0.03), glutathione (P < 0.01) as well as creatinine kinase (P < 0.05) were more markedly elevated when compared with survivors. CONCLUSION: Although there were severity-dependent as well as pattern-related releases of various mediators, which in part were more apparent in nonsurviving patients, we failed in proving any predictive marker to specifically discriminate outcome.

Accidents↗

PubMed1998

Early posttraumatic increase in production of nitric oxide in humans.

Since nitric oxide (NO) contributes to both circulatory disorders and host defense, we analyzed the NO production in (poly)trauma patients (pts) in a prospective (pre)clinical study starting as early as at the scene of accident. Upon approval of the local IRB/EC, 85 multiple injured pts were enrolled. Subsets were performed according to trauma severity (ISS) and injury pattern, and between survivors versus nonsurvivors. The first blood sample was collected at the scene of accident, then in hourly to daily intervals. NO production was assessed by measuring nitrate+nitrite plasma levels. To estimate dilution effects, all values were calculated according to the actual plasma protein content. The extent of trauma was appraised by C-reactive protein (CRP) levels. Immediately after trauma, NO2-+NO3- plasma levels were always elevated. This was most pronounced in thoracic injury, irrespective of whether it was combined with multiple trauma. Nitrate+nitrite levels returned to normal within 24 h. CRP generation increased during 12 h following trauma and was most marked in severest trauma (ISS >50). For the first time, we show very early data following major trauma that demonstrate that NO overproduction starts immediately after trauma. However, systemic NO2-+NO3- levels actually reflect the severity of injury only during the first 2 h. Thereafter, NO generation is rather related to the individual trauma pattern, e.g., chest trauma. Nonetheless, the role of NO after severe trauma and especially in thoracic injury remains unclear and should further be elucidated in a specific study.

Adolescent↗

PubMed1998

[Monitoring ischemia-/reperfusion syndrome in abdominal aortic aneurysm--conventional operation versus stent implantation].

From a biochemical point of view, our study corroborates the suggestion that implantation of a stent graft is less invasive than conventional surgery for infrarenal aortic aneurysm. In general, ischemia during open aortic surgery lasts shorter but affects a much greater part of the body than stent implantation. Eventration before, and more pronounced reperfusion following conventional repair cause marked intra-operative increases in TxB2, 6-keto-PGF1 alpha, and sICAM-1 levels. Thromboxane obviously is generated mainly in the reperfused tissues, whereas 6-keto-PGF1 alpha is produced in the eventrated bowel. sICAM-1 is released from both.

Aortic Aneurysm, Abdominal↗

PubMed1998

[Detection of NO liberation in the early phase of trauma].

Both, burn trauma and sepsis induce the generation of reactive oxygen intermediates which often coincides with increased nitric oxide (NO) levels. NO takes part in both circulatory disorders and cell protection. Therefore, in a prospective (pre-)clinical study we focused on the detection of NO in polytrauma patients (pts) starting as early as at the scene of accident. Upon approval of the local ethics committee, pts with an injury severity score (ISS) ranging from 9 to 75 (mean 22) were enrolled. Subsets were performed according to the different injury pattern (long bone fractures, head injury, polytrauma with and without damage to the thorax, isolated chest trauma). The first blood sample was obtained at the scene of accident. Then, blood was collected in hourly to daily intervals. NO production was assessed by the nitrate + nitrite plasma levels. To eliminate dilution effects following volume substitution, all values were recalculated on the plasma protein content. Immediately after trauma, NO plasma levels were elevated. This was most pronounced in pts that have experienced thoracic injuries irrespective of with or without additional polytrauma. There is evidence that NO production always starts immediately after major trauma but depends on the individual trauma pattern. In addition, the results reveal that lethal outcome is associated with an increased NO generation in the early post-injury period. We conclude that NO overproduction does not necessarily prime an overall protection in patients that have suffered from mechanical trauma. The role of NO after severe trauma and especially in thoracic injury should further be elucidated in a specific study on that topic.

Adult↗

PubMed1997

Is the activity of soluble CD14 enhanced following major trauma?

BACKGROUND: The molecule CD14 acts as a receptor for the protein-bound endotoxin (lipopolysaccharide [LPS]) complex and mediates the cellular effects of LPS. The soluble formation, sCD14, is supposed to neutralize circulating LPS (i.e., LPS antagonist) or transfer LPS effects to endothelial cells (i.e., LPS agonist). OBJECTIVE: To elucidate the release of sCD14 per se in patients with major trauma in the early posttrauma period. Our a priori hypothesis was that sCD14 release depends on the plasma LPS concentration simultaneously measured. PATIENTS: In a prospective study, 65 patients with multiple injuries (Injury Severity Score, 9-75) were enrolled. The patients were rescued by the medical helicopter service and directly admitted to our clinics. The plasma concentrations of sCD14 (enzyme immunoassay) and LPS (chromogenic limulus amebocyte lysate test) were analyzed. The first blood sample was collected immediately at the accident site. The following samples were drawn at intervals from 2 hours to daily for 2 weeks. RESULTS: Sixty-one patients survived the observation time. Immediately after trauma, their mean sCD14 level was not different from that of healthy individuals. Two hours later, a pronounced increase of sCD14 was observed and sustained throughout the observation period. Even nonsurvivors showed an increased sCD14 release, but less pronounced. In all patients, plasma LPS levels were elevated during the first 12 hours. CONCLUSIONS: Major trauma caused an increased release of sCD14. This elevation, however, was not correlated to LPS levels or to the severity of trauma (estimated by trauma scores). We found no evidence that sCD14 levels are of prognostic value regarding survival. Furthermore, the release of sCD14 did not occur in an LPS-neutralizing manner, but rendered possible an LPS-independent mechanism.

Adolescent↗

PubMed1997

Improved methods to measure end products of nitric oxide in biological fluids: nitrite, nitrate, and S-nitrosothiols.

The aim of this study was to compare and improve standard methods to determine nitrite (NO2-), nitrate (NO3-) and S-nitrosothiol (RSNO) levels in cell culture supernatants, sera, and urine. We modified the conventional Griess reaction by replacing sulfanilamide with dapsone (4,4'-diamino-diphenylsulfone) and compared the NO2- levels in our study samples with a commercially available NO2- assay kit. Our modification, along with ultrafiltration of the samples, resulted in an enhanced sensitivity to measure NO2- down to 0.2 microM. The detection limit was further improved to 0.02 microM when NO2- was identified by the fluorochrome 2,3-diaminonaphthalene (DAN). To measure the stable end product NO3- by the Griess reaction or the DAN method, this anion must be reduced to NO2-. We compared the capacity of bacterial nitrate reductase with the reducing metal cadmium to convert NO3- to NO2-. After reduction, NO2- levels were determined either by the DAN method or by our modified Griess reaction. We found that there was a high correlation (r2 = 0.998) in total NO2- concentrations in the study samples using both methods for reducing NO3- to NO2-. The simultaneous determination of NO2- and NO3- was achieved by using anion-exchange chromatography (HPLC; Polyspher IC AN-1 column). The detection limit of this assay for each anion is 0.5 microM, and it can be applied equally well to sera, urine, and culture media. We also adapted the DAN method to determine RSNO levels in our study samples. Using this approach, we were able to measure RSNO levels down to 0.15 microM. As result we discovered that RSNO levels were markedly increased in urine from septic patients and in supernatants from cytokine-stimulated human tumor cell lines. L-Citrulline, a coproduct of NO biosynthesis, was measured using a colorimetric assay with a sensitivity limit of 3.0 microM. Increased L-citrulline levels in media from cultured cells, but not in sera or urine, correlated with increased NO production. Although all methods studied were suitable for quantifying end products of NO in biological fluids and media, the use of bacterial reductase and the modified Griess reaction proved successful to provide the greatest sensitivity and linear range for routine measurements of NO2- and NO3-.

Body Fluids↗

PubMed1997

[Liberation of soluble CD14 (sCD 14) in plasma of trauma patients].

Membrane-fixed CD14 acts as a receptor for the protein-bound endotoxin (LPS) complex and mediates the cellular effects of endotoxin. Soluble CD14 (sCD14) is suggested to neutralize circulating LPS, i.e., acting as an endotoxin antagonist. The aim of this study was to elucidate the release of both sCD14 and endotoxin in traumatized patients, starting from the earliest phase after trauma. A total of 15 patients (O ISS = 19, 9-75) suffering major trauma were enrolled in this prospective study. Blood samples were collected as early as immediately at the site of accident, on hospital admission, and thereafter hourly, then daily. For patients (O ISS = 47) died within 24 h because of their severe injuries. Immediately after the accident as well as during the first 2 h after hospital admission, the mean sCD14 levels of surviving patients did not differ from those of healthy volunteers (n = 53). Thereafter, however, sCD14 increased continuously in the trauma group. The concentrations remained elevated throughout the entire observation period. There was, however, no relation between the sCD14 release and the pattern or the severity of injury. In contrast, endotoxin levels revealed a pattern-specific release. The highest plasma concentrations of LPS were observed in patients suffering from (additional) thoracic injury. On the basis of these results we conclude that the release of sCD14 after trauma does not reflect a strict principle such as action/reaction caused by the appearance of endotoxin immediately after the injury. Soluble CD14 is more likely release by an endotoxin-independent mechanism.

Adolescent↗

PubMed1997

Isovolemic hemodilution with a bovine hemoglobin-based oxygen carrier: effects on hemodynamics and oxygen transport in comparison with a nonoxygen-carrying volume substitute.

OBJECTIVE: Stroma-free hemoglobin solutions have been shown to maintain oxygen transport in the absence of red blood cells. This study was designed to investigate the impact of such solutions on hemodynamics and oxygen transport during progressive isovolemic hemodilution within and even beyond a clinically relevant range of hematocrit values. DESIGN: Prospective, randomized experimental study comparing a bovine hemoglobin-based oxygen carrier (bHBOC) with a conventional nonoxygen-carrying volume substitute (hydroxyethyl starch [HES]). SETTING: Animal laboratory of a university cardiovascular research center. PARTICIPANTS: Splenectomized full-grown foxhounds, anesthetized with pentobarbital and piritramid. INTERVENTIONS: Twelve splenectomized foxhounds were anesthetized and mechanically ventilated. Catheters were placed for hemodilution, arterial and venous blood sampling, and hemodynamic measurements. The baseline hematocrit (Hct) value was adjusted to 0.35 by an initial isovolemic exchange of blood for identical volumes of HES (10% HES 200/0.5). Thereafter, the hematocrit was progressively reduced by isovolemic hemodilution using either HES (n = 6) or bHBOC (n = 6). MEASUREMENTS AND MAIN RESULTS: Hemodynamic and laboratory parameters of oxygen transport were measured at Hct values of 0.30, 0.20, and 0.10. Oxygen content was directly estimated using an oxygen-specific fuel cell. Arterial oxygen content at an Hct value of 0.10 nearly doubled in bHBOC-treated dogs as compared with HES-diluted animals (p < 0.001). This gain in oxygen-carrying capacity was completely negated by a decrease in cardiac output (-32% Hct 0.35 v Hct 0.30; p < 0.001) immediately on the first infusion of bovine hemoglobin. Thus, oxygen delivery was significantly lower as compared with HES-treated dogs at Hct 0.30 and 0.20, but remained stable at a level of 60% of baseline until Hct was 0.10. Both the pulmonary and the systemic vascular resistances increased. CONCLUSIONS: Isovolemic hemodilution with bHBOC did not improve systemic oxygen delivery in comparison with a nonoxygen-carrying diluent (HES) in a range of Hct values down to 0.10. Unchanged mixed venous lactate levels and stable oxygen consumption indicate sufficiently maintained oxygen delivery. This might become advantageous in patients who are unable to adequately increase cardiac output during hemodilution.

Animals↗