PubMed Health⌕ Search

Biomedical subjects

H Redl

Publications and source records attributed to H Redl.

At least 109 records · Page 6Linked to original sources
PubMed1993

Complement activation in septic baboons detected by neoepitope-specific assays for C3b/iC3b/C3c, C5a and the terminal C5b-9 complement complex (TCC).

We have investigated the cross-reactivity of various species in neoepitope-specific methods for quantification of human complement activation products. In contrast to most other species examined, baboon showed a substantial cross-reactivity supporting a high degree of homology between human and baboon complement. An assay for C3b, iC3b and C3c (MoAb bH6) showed moderately good reactivity, in contrast to a C3a assay which did not cross-react. Excellent reactivity was found for C5a using MoAbs C17/5 and G25/2. The reactivity of an established TCC assay (MoAb aE11 to a C9 neoepitope and polyclonal antibody to C5) was improved substantially by replacing the anti-C5 antibody with a new MoAb to C6 particularly selected on the basis of baboon cross-reactivity. Plasma samples from baboons receiving 2.5 x 10(9) and 1.0 x 10(10) live Escherichia coli bacteria/kg were examined with the assays described. In vivo complement activation with the lowest dose was moderate and kept under control, in contrast to the highest dose, where an uncontrolled increase in all activation products continued throughout the infusion period. These results support the hypothesis that sufficiently high amounts of endotoxin lead to uncontrolled activation of complement as seen in irreversible septic shock. The results are discussed with particular emphasis on activation of the terminal complement pathway.

Animals↗
PubMed1993

Tumor necrosis factor is a mediator of phospholipase release during bacteremia in baboons.

Phospholipase A (PLA) activity is elevated in plasma after polytrauma and in sepsis. During both situations, tumor necrosis factor (TNF) and free fatty acids (FFAs) are also increased. To determine whether there is a relationship between the changes in PLA and in TNF that occur during sepsis, we used a primate model of bacteremia. Live Escherichia coli (5 x 10(8) colony-forming units/kg) was injected into anesthetized baboons (n = 10). Four of these animals were pretreated with an anti-TNF antibody (anti-TNF Ab, 15 mg/kg). After the administration of bacteria (2 h), the plasma TNF was 10.2 +/- 3.2 ng/ml. PLA and FFA reached their maximum values of 191 +/- 14 U/l and 1.5 +/- 0.3 mM at 10 and 24 h after the injection of bacteria, respectively. In the animals treated with anti-TNF Ab, plasma TNF was undetectable; the highest values recorded for PLA and FFA were 71 +/- 23 U/l and 0.7 +/- 0.3 mM, respectively. Thus TNF appears to be an important mediator of PLA release during sepsis.

Animals↗
PubMed1993

Endothelial and leukocyte activation in experimental polytrauma and sepsis.

Vascular endothelial-PMN interactions are critical reactions in the development of organ failure. Both cell types are activated by LPS and proinflammatory cytokines in sepsis. Reactions that are collectively referred to as endothelial activation include expression of procoagulant activity and increased adhesiveness of the endothelium for leukocytes. Some parameters, which are related to endothelial activation are significantly changed during sepsis and altered by anti-TNF therapy (e.g. PAI-1, thrombomodulin), while others (e.g. sELAM) are increased by sepsis but not influenced by anti-TNF therapy. Leukocyte activation (accompanied by elastase release) leads to rearrangement of the CD11/CD18 structures and thereby increased adherence.

Animals↗
PubMed1993

Early osteoinduction in rats is not altered by fibrin sealant.

The angiogenic and fibrogenic activities of fibrin sealant (Tisseel) suggest that it could enhance osteoinductivity during the first days after implantation. To test this hypothesis, the osteoinductivity of sealed and unsealed bone matrix gelatin was tested by implantation into rat abdominal wall muscle pouches for two to ten days. A sponge of collagen with or without fibrin sealant was used for control. Alkaline phosphatase (ALPase) was employed to quantify osteoinduction, and myeloperoxidase (MPO) was used to determine the inflammatory reaction. Plain histologic analysis of bone matrix gelatin implants at Days 2, 4, and 10 did not demonstrate any significant differences between sealed and nonsealed implants. Histologic analysis at Day 21 confirmed the osteoinductivity of the implant. The combination of bone matrix gelatin and fibrin sealant induced an early significant increase in ALPase activity, which could be interpreted as early induction of histologically undetectable osteogenesis. A simultaneous increase in the level of MPO suggested that the bone matrix gelatin/fibrin sealant-induced ALPase reaction might be caused by an inflammatory process, but neutrophil counting did not correlate to the MPO data. Morphometry, however, seems to be insufficient to assay a heterogenous histologic distribution of singular cells. It is proposed that the ALP/MPO ratio may be used as an inflammation-independent marker of osteogenesis. This study does not support the notion of an osteoinductive potency of fibrin sealant per se; however, it is clear that fibrin sealant does not impair bone matrix gelatin-dependent osteoinduction.

Abdominal Muscles↗
PubMed1993

Complement and leukocyte activation in septic baboons.

The effect of Escherichia coli infusion on complement and leukocytes was evaluated in a baboon model. During 8 hr, different amounts of live E. coli (5 x 10(8), 2.5 x 10(9) and 10(10) live bacteria kg body weight) were infused. Twenty-one baboons were investigated. Activation of complement (terminal C5b-9 complement complex; TCC) and activation of leukocytes (PMN elastase) and plasma concentrations of endotoxin (lipopolysaccharide; LPS) were determined before the start of bacteria infusion and 2, 4, 6, and 8 hr after the start of infusion. In baboons receiving 2.5 x 10(9) and 10(10) live E. coli per kilogram body weight, increasing plasma levels of TCC were found (P < 0.05). No significant alterations of TCC were observed when animals were infused with 5 x 10(8) live E. coli per kilogram body weight during an 8 hr period. Plasma levels of PMN elastase increased significantly in baboons receiving 5 x 10(8), 2.5 x 10(9), and 10(10) live bacteria per kilogram body weight. High levels of LPS were detected in animals receiving 10(10) live E. coli bacteria per kilogram body weight and in animals receiving 5 x 10(8) or 2.5 x 10(9) live E. coli bacteria per kilogram body weight. There was a positive correlation between the formation of TCC and the plasma levels of PMN elastase and LPS and between plasma levels of PMN elastase and of LPS. Activation of complement and leukocytes may contribute to the development of organ dysfunction seen in baboons infused with high amounts of live E. coli.

Animals↗
PubMed1992

Influence of the xanthine derivate HWA 138 on endotoxin-related coagulation disturbances: effects in non-sensitized vs D-galactosamine sensitized rats.

We have evaluated the effects of the xanthine derivate HWA 138 in rat endotoxemia in order to 1) prevent coagulation disturbances and other endotoxin-induced physiological abnormalities and 2) to reduce mortality. We performed two studies using two different models (sensitized vs non-sensitized rats) with a similar mortality but different severity of coagulation disturbances: a) LPS (15 mg/kg) alone or with HWA 138 (80 mg/kg) as a treatment modality 30 min pre LPS, b) galactosamine (500 mg/kg) simultaneously with LPS (100 micrograms/kg) with or without HWA 138 (80 mg/kg) pretreatment. Experiments c) and d) employed D-galactosamine and/or LPS similar to experiments a) and b), while HWA 138 was applied simultaneously. We found significant 1) amelioration of life-threatening coagulation disturbances in non-sensitized rats, 2) prevention of liver dysfunction in sensitized rats, 3) reduction of TNF formation in both models, and 4) improvement of survival in all groups receiving HWA 138. Our data indicate protective effects of HWA 138 against clotting disturbances either directly via reduced LPS-induced formation of procoagulant activity or indirectly via reduced TNF formation.

Animals↗
PubMed1992

Superoxide dismutase and catalase in an experimental model of multiple organ failure.

Multiple organ failure (MOF) can be induced by sterile intraperitoneal injection of zymosan in the rat. This results in a typical triphasic illness with maximal clinical signs at Days 2 and 12. In this model, superoxide production and lipid peroxidation closely correlate with the triphasic clinical illness. In the present experiment we studied the effect of albumin conjugated superoxide dismutase (SOD) and catalase (CAT) on lipid peroxidation and organ damage in the acute phase (Days 1 and 2). Lipid peroxidation in plasma was significantly decreased by SOD and CAT but clinical condition, mortality, and organ damage did not improve. We conclude that oxygen radical damage is not a key factor in the pathogenesis of the acute phase of multiple organ failure.

Animals↗
PubMed1992

Cryopreservation of cytological specimens for immunocytochemistry.

A method has been established for storage and preservation of cytological specimens in liquid nitrogen and further processing for immunocytochemistry as smears prepared from thawed cells or cryo-sections of frozen cell pellets. For the experiments cultured cells of a T-lymphoblastic leukemia cell line (ATCC CCL 119) and blood cells of the buffy coat of healthy humans were treated with a cryo-solution (fetal calf serum +5% dimethylsulfoxid) and after freezing stored in liquid nitrogen. Alternatively, cells preincubated with cryo-solution followed by suspension in fetal calf serum without cryo-additive were frozen and stored in liquid nitrogen for the production of cryo-sections. Indirect immunofluorescence and alkaline phosphatase--antialkaline phosphatase based immunoreactions were performed for the decoration of various surface antigens with a panel of monoclonal antibodies. All immunoreactions were repeated at least three times and the stored cell preparations were investigated after different periods of storage (up to four months). The immunoreactions of fresh cells in suspension (which were used as controls) were comparable with those of cryopreserved cells, e.g. cells on smears after thawing and on cryo-sections of cell pellets. The strongest immunoreactions were achieved on fixed cryo-sections. The maintenance of cell morphology of smears from cryopreserved cells was slightly better than of cells from cryo-sections. In our hands the preparation of cell pellets, which are suitable for the storage in liquid nitrogen and the production of cryosections, is a very useful method for immunocytochemical investigations of cytological specimens especially in situations where immunoreactions cannot be performed on fresh material.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1992

Inhibition of human, ovine, and baboon neutrophil elastase with Eglin c and secretory leukocyte proteinase inhibitor.

The association rate constants (kon) of human, ovine, and baboon neutrophil elastase with two recombinant serine proteinase inhibitors (Eglin c, secretory leukocyte proteinase inhibitor) were compared. The association rate constant of sheep leukocyte elastase (SLE) with Eglin c is about 100 times lower (kon = 2.2 x 10(5) M-1s-1) than that of human elastase (kon = 2.4 x 10(7) M-1s-1). Baboon elastase, however, is as effectively blocked with Eglin c (kon = 2.5 x 10(7) M-1s-1) as human elastase. Secretory leukocyte proteinase inhibitor (SLPI) blocks the elastase of all three species with high efficiency; baboon elastase shows the highest association rate constant (kon = 5.6 x 10(7) M-1s-1) followed by human elastase (kon = 4.1 x 10(7) M-1s-1) and finally sheep elastase (kon = 1.2 x 10(7) M-1s-1). These findings demonstrate marked differences in the inhibition kinetic properties of ovine and human elastase. Concerning a future clinical application of proteinase inhibitors, the baboon seems a more suitable model than sheep to evaluate the effects of Eglin c and SLPI, since both inhibitors block baboon and human elastase with comparable efficiency.

Animals↗
PubMed1992

The enzymatic and release characteristics of sheep neutrophil elastase: a comparison with human neutrophil elastase.

Sheep are often used to study tissue damage following shock after traumatic injury and in the course of other diseases. The processes involved are thought to be caused at least in part by elastase released from polymorphonuclear leukocytes (PMNs). Since little is known about elastase and its role as a mediator of tissue damage in sheep, we studied the biochemical properties and release characteristics to sheep leukocyte elastase (SLE) in comparison of those of human leukocyte elastase (HLE). Both enzymes showed similar molecular masses, amino-acid compositions, N-terminal amino-acid sequences, and abilities to digest elastin substrates. Differences, however, were found in kinetic parameters measured with the elastase-specific substrate N-methoxysuccinyl-(L-alanyl)2-L-prolyl-L- valine-4-nitroanilide (MeoSuc-AAPV-pNa). The Michaelis constant (Km) of ovine elastase was nearly 10 times higher (1.82 mM) than the Km of HLE (0.21 mM). Values of SLE calculated for kcat were 70% and for kcat/Km 8% of corresponding values determined for HLE. In addition, significant differences between sheep and human PMNs were found in in vitro stimulation experiments. In contrast to human PMNs, sheep neutrophils released no active elastase, and only 50 to 70% of the H2O2 produced by human PMNs. This failure to release active elastase could not be explained by a lower elastase content of sheep PMNs, as there were no significant differences found between the elastase contents of sheep and human PMNs. We conclude that elastase liberated by stimulated sheep PMNs is inactivated by a concomitantly released proteinase inhibitor also located within the sheep PMNs.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Hyperdynamic sepsis in baboons: II. Relation of organ damage to severity of sepsis evaluated by a newly developed morphological scoring system.

The purpose of our study was to set up a baboon hyperdynamic sepsis model with live bacteria administration, which produces within 8 hr an organ failure comparable to human pathological conditions. Twelve adult male baboons were instrumented and studied for 8 hr under pentobarbital (2-3 mg/kg BW/hr) anesthesia breathing spontaneously. The animals were divided into two groups: 1) Live Escherichia coli were infused intravenously at a dose of 1.0-2.0 x 10(10) CFU/kg BW over 8 hr; 2) Live E. coli were infused i.v. at a dose of 5 x 10(8) CFU/kg BW over 2 hr. Organ damage was monitored by a newly developed scoring system. Organ damage was clearly dependent on the concentration of the bacterial challenge. Bacterial challenge at a dosage of 5.0 x 10(8) produces insignificant hemodynamic effects, while the 1.0-2.0 x 10(10) animals demonstrated massive hemodynamic alterations and needed much higher fluid support. The higher E. coli dosage was associated with an overwhelming organ damage seen, e.g., from the lung weight (12 g/kg BW vs. 9.6 g/kg BW with the lower dosage) or from the organ failure score, which is based on macroscopic pathology, histological data and organ weight. The percentage of animals with one, two, or three organ failures (organ failure score > or = 2) was higher in baboons with the higher dosage/kg BW. Therefore, we believe that the less severe organ damage in the acute phase after 8 hr with live bacteria 5 x 10(8) CFU/kg BW infusion over 2 hr is better to monitor the efficacy of newly developed therapeutic regimens, since in another set of experiments this model still produces lethal organ damage (80%) in a subchronic setting over 72 hr.

Adrenal Glands↗
PubMed1992

Functional analysis of monocyte activity through synthesis patterns of proinflammatory cytokines and neopterin in patients in surgical intensive care.

This study was designed to further differentiate monocyte behavior in critically ill patients with operative or accidental trauma. The patient population studied consisted of 39 patients (17 patients undergoing elective surgery [ES], seven patients with major multiple injuries [MI], and 15 patients in an acute septic state [S]). Immunologic parameters assessed included monocyte phenotyping with the monoclonal antibody LeuM3, measurement of the cytokines interleukin (IL)-1, IL-6, and IL-8 in lipopolysaccharide-stimulated in vitro cultures of mononuclear leukocytes (PBMCs), and determination of neopterin in gamma-interferon-stimulated in vitro cultures and corresponding serum samples. Serum neopterin levels were very high in S patients (89.0 nmol/L; p less than 0.05) compared with control values (4.6 nmol/L), with a rise to 16.4 nmol/L in ES patients on day 7 and 13.4 nmol/L in MI patients on day 7. The concentrations of gamma-interferon-induced neopterin in the supernatants of the PBMC cultures were elevated in all patient groups. Severe impairment of IL-1 synthesis was seen in MI and S patients. IL-8 synthesis (818 +/- 150 units/ml, control value) was also suppressed (p less than 0.05) in MI patients; the values were 135 +/- 65 units/ml on day 1,231 +/- 110 units/ml on day 3,347 +/- 131 units/ml on day 7, and 355 +/- 107 units/ml in S patients. The kinetic patterns of synthesis were comparable for IL-1 and IL-8 in all patient groups. Lipopolysaccharide-induced IL-6 synthesis (9.4 +/- 1.5 x 10(3) units/ml, control value) was significantly elevated in the PBMC cultures of all patient groups, with the exception of the early phase after accidental trauma. Maximum amounts of IL-6 synthesis after surgery were 19.6 +/- 7 x 10(3) units/ml in S patients and 19.0 +/- 2.2 x 10(3) units/ml in ES patients. These results demonstrate (1) the impairment of the functional capacity of circulating monocytes and (2) that the degree of functional impairment is proportional to the severity of the injury.

Adolescent↗
PubMed1992

Special collection and storage tubes for blood endotoxin and cytokine measurements.

Commercially available blood-collection tubes may be contaminated with endotoxin (315 +/- 95 pg/tube) and could therefore be unsuitable for blood collection for endotoxin measurement. Plasma separation and storage are a potential source of contamination. To avoid contamination and error, we have developed new blood collection tubes that contain heparin free of endotoxin (LPS) and a gel to separate plasma and blood cells. The LPS content is less than 4 pg/tube. Samples can be stored and frozen without plasma withdrawal to preclude contamination. LPS recovery experiments have shown that the new blood-collection tubes do not bind LPS to the separation gel or vial wall. With these tubes, in vitro formation of tumor necrosis factor (404 +/- 163 ng/L in standard tubes vs less than 40 ng/L in special collection tubes) is minimized.

Blood Specimen Collection↗
PubMed1991

The cell in shock: the origin of multiple organ failure.

The immediate organ damage seen after multiple trauma and in shock is a typical example of non-bacterial inflammation triggered by activation of various mediators of both the humoral and cellular systems. Anaphylatoxins and the low-flow syndrome during the shock phase account for increased PMN* margination, which in turn causes pulmonary leukostasis and may provoke massive mediator release by PMN (oxygen radicals, proteinases, eicosanoids, PAF etc). This probably leads to severe endothelial cell damage, especially in the lung. Adherence of PMN to the endothelium appears to create the micro-environment where high concentrations of proteolytic enzymes and reactive oxygen radicals exert a deleterious effect on the cell membrane. Endothelial cell membrane injury leads to increased vascular permeability and cell edema. The development of the 'organ in shock' may require a few hours and initially cause minor or no functional impairment at all. Only when shock is severe is there early organ failure, which in this stage may still be an expression of non-bacterial inflammation. Numerous studies have reported the existence of shock-induced cardiodepressant substances in association with various forms of circulatory shock. We have determined a net negative inotropic effect of the low-molecular-weight plasma fraction in severe hypovolemic-traumatic shock and have isolated a cardiodepressant factor (CDF), which by blockade of the calcium inward current has a negative inotropic a chronotropic effect. The intestine as a shock organ appears to range first among the organs involved. The translocation of bacteria from the intestinal tract, the 'intestine in shock' represents the trigger reaction that eventually leads from the 'organ in shock', early organ failure to late (septic) organ failure. Here the most prominent factor is endotoxin (LPS) as a basic mediator of gram-negative bacteria, which also triggers the activation of humoral and cellular systems. The posttraumatic hyperdynamic phase commonly starts on days 3-5 and is mainly caused by bacteremia and/or endotoxemia. Macrophages have a major impact on the late phase of organ failure. At present, the most prominent cellular mediator of the lethal effect of endotoxin is thought to be cachectin, which is identical with the tumor necrotising factor (TNF). TNF is secreted by monocytes/macrophages (MO/MA) in response to LPS. Via macrophage derived cytokines and by LPS there is activation of endothelial cells, with increased adhesiveness for PMN. Both due to this increased adhesiveness and the presence of LPS and cytokines, PMN undergo massive activation, which causes mediator release and tissue damage.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Plasma neutrophil-activating peptide-1/interleukin-8 and neutrophil elastase in a primate bacteremia model.

A hyperdynamic sepsis model was set up in seven adult baboons to evaluate neutrophil-activating peptide-1/interleukin (IL)-8 (NAP-1/IL-8), IL-1 beta, IL-6, tumor necrosis factor-alpha (TNF alpha), and IFN-gamma in plasma. By continuous intravenous administration of 10(10) cfu/kg live Escherichia coli over 8 h with additional infusion therapy (less than or equal to 50 ml/kg/h), endotoxin plasma levels of 2.7-22.3 ng/ml were observed. In plasma the kinetics of NAP-1/IL-8 and IL-6 were similar to those of IL-1 at the end of the experiment (8 h) (peak median values, 34, 4197, and 230 ng/ml, respectively). Differences were greatest for IL-6. Monocyte activation during sepsis was confirmed by elevated plasma neopterin levels (91-139 mumol/mmol of creatine). Granulocyte activation was evident from both incipient neutropenia and the massive release of neutrophil elastase into the plasma as measured by a new immunoassay (peak level, 374 ng/ml). Thus, in primate bacteremia, early TNF release is followed by a concomitant increase of NAP-1/IL-8 with plasma kinetics similar to those of IL-6 and IL-1 and accompanied by massive activation of neutrophils.

Animals↗
PubMed1991

Fresh autogeneic, frozen allogeneic, and decalcified allogeneic bone grafts in dogs.

In fully-grown mongrel dogs, diaphyseal ulnar defects 25 mm long were stabilised by screws and plates, and were temporarily filled with silicone rubber blocks. After eight weeks the block was replaced either by fresh autogeneic cancellous bone, allogeneic deep-frozen cancellous bone, allogeneic decalcified bone matrix, or bone matrix gelatin. After 24 weeks the implants were evaluated by radiography, histology, and measurements of new bone volume, using computer-assisted density registration on microradiographs. Only the autogeneic bone grafts led to healing in all instances. Bone regeneration in the other groups was not significantly better than in the sham group in which no graft was employed. Decalcified bone matrix proved ineffective.

Animals↗
PubMed1991

Expression of endothelial leukocyte adhesion molecule-1 in septic but not traumatic/hypovolemic shock in the baboon.

Baboons were subjected to septic or traumatic/hypovolemic shock and their tissues were examined for the de novo expression of endothelial leukocyte adhesion molecule 1 (ELAM-1), using immunohistochemical techniques. In animals with septic shock induced with live Escherichia coli, there was widespread expression of ELAM-1, recognized by monoclonal antibodies H4/18 or ENA-1 in most tissues examined with strong staining in the lung, liver, and kidneys. Endothelial leukocyte adhesion molecule 1 expression was evident in capillaries, venules, small veins, arterioles, and arteries. In contrast, baboons with traumatic/hypovolemic shock had minimal levels of focal ELAM expression in all organs studied. Similarly evidence of neutrophil activation, measured by granulocyte elastase levels in the plasma was much more pronounced in animals with septic shock. The study documents that lipopolysaccharide (LPS)- and cytokine-induced endothelial activation occurs in vivo in septic shock. Much higher levels of ELAM-1 expression and plasma granulocyte-elastase titer in septic shock, as contrasted with traumatic/hypovolemic shock, are consistent with the higher levels of circulating tumor necrosis factor, other cytokines, and LPS in sepsis.

Animals↗