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G Schlag

Publications and source records attributed to G Schlag.

At least 109 records · Page 6Linked to original sources
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

Septic focus localized by determination of arterio-venous difference in neopterin blood levels.

We describe a case of a 38-year-old female accident victim who was admitted to the trauma hospital with an ISS of 66. Successful emergency treatment (including amputation of the left leg) and 4 weeks of intensive care led to an overall improvement so that the patient was extubated on day 29. Throughout this period neopterin was measured routinely 3 times a week and correlated well with the clinical course. At the end of the fifth week massive lung impairment and all clinical signs of sepsis appeared. Neopterin values increased dramatically up to 200 nmol/L. However, no abnormal findings were revealed by X-ray, contrast fluoroscopy, or sonographic imaging. To examine the amputation site more closely, simultaneous determination of neopterin in samples from the vena and arteria femoralis was performed. We found a 50% higher level in the venous blood (300 vs. 200 nmol/L). This was regarded as evidence for a hidden focus. Immediate surgical intervention revealed an abscess, which proved to be Pseudomonas aeruginosa positive. After adequate treatment the patient recovered quickly. In this case neopterin was not only helpful in monitoring the septic episodes of the patient, but proved essential for the detection of a septic focus and the risk of explorative relaparotomy could be omitted.

Abscess↗
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

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

Characterization of phosphatidylcholines in rabbit lung lavage fluid by positive and negative ion fast-atom bombardment mass spectrometry.

The relative distribution of intact diacylphosphatidylcholine species isolated from the lung lavage fluid of rabbits has been investigated by positive ion fast-atom bombardment (FAB) mass spectrometry. Two different isolation/purification methods were applied and evaluated prior to mass spectrometric analysis. The first method consisted of a Bligh and Dyer extraction of the lung lavage fluid followed by isocratic high-performance liquid chromatographic (HPLC) separation. In the second method a thin-layer chromatographic purification step was introduced between the extraction procedure and the HPLC separation. Further, the FAB matrices glycerol and 3-nitrobenzyl alcohol were used, and their influence on the diacylphosphatidylcholine molecular ion species was studied. The Bligh and Dyer extraction followed by the simple HPLC separation was the method of choice to obtain stable, long-lasting protonated molecular ions and diagnostic fragment ions, which permitted the identification of the polar head-group. In combination with 3-nitrobenzyl alcohol as liquid matrix we established a procedure that yielded a fast sample preparation method, a good signal-to-noise ratio for detecting minor species, and reduced formation of [M+H-2H]+ ion species. The relative fatty acid composition of the diacylphosphatidylcholine fractions isolated from rabbit lung lavage fluid was determined by negative ion FAB mass spectrometry using the carboxylate anions. The mass spectrometric results were compared with those acquired by gas chromatographic determination of the fatty acid methyl esters. Close agreement was found between the data obtained by the two independent methods.

Animals↗
PubMed1991

Decalcified and undecalcified cancellous bone block implants do not heal diaphyseal defects in dogs.

UNLABELLED: In a previous study it has been shown that granulae of decalcified bone matrix do not induce bony healing of 8-week-old mid-diaphyseal defects in dogs. The aim of this study was to test whether osteoinduction combined with the osteoconductive mechanisms provided by the natural structure of cancellous bone blocks would yield better results. A 30-mm-long diaphyseal defect of the left ulna was created in eight adult mongrel dogs and the bone was stabilized with a plate. A Silastic spacer was inserted in the defect for 8 weeks, followed by implantation of frozen undecalcified or decalcified allogeneic cancellous bone blocks for 16 weeks. Healing was analyzed using morphologic methods. At 16 weeks after implantation all grafts had been resorbed. In the decalcified group one defect healed, while none in the other group did so. The implant material was bioassayed in nude rats for osteoinductivity, which was found to be low in decalcified matrix and not detectable in undecalcified bone. CONCLUSION: Allogeneic cancellous bone blocks, demineralized or not, have no osteoinductive capacity and no osteoconductive function that promotes healing of mid-diaphyseal bone defects in dogs.

Animals↗
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

A cardiodepressant factor isolated from blood blocks Ca2+ current in cardiomyocytes.

A cardiodepressant factor (CDF) was isolated (salt free) from the plasma of dogs after hypovolemic-traumatic shock by column chromatography. CDF was found to exert a concentration-dependent negative inotropic effect in guinea pig papillary muscle; it reduced the amplitude of cell wall motion, the contraction and relaxation velocity, and the frequency of spontaneously beating rat cardiomyocytes in culture, effects that were rapidly reversible upon washout. By means of electrophysiological methods (whole cell recording with patch electrodes and voltage clamp) we tested the effect of CDF on adult guinea pig cardiomyocytes: application of CDF initially decreased the plateau by 7 mV (150 ms after peak of action potential) and reduced the action potential duration by 93 ms (76% of control action potential duration) at 50% and 88 ms (79%) at 90% of repolarization. The plateau was further reduced by 13 mV and the action potential duration was prolonged by 25 ms (106%) at 50% and was prolonged drastically by 156 ms (137%) at 90% of repolarization compared with control. Voltage-clamp experiments have shown that the most prominent effect of CDF is a strong reduction of ICa accompanied by inhibition of IK and subsequent repolarization. Similar results have been obtained with neonatal rat cardiomyocytes. Blockage of the calcium inward current can explain the negative inotropic and chronotropic effect of CDF in cardiomyocytes.

Action Potentials↗
PubMed1991

Cardiac dysfunction after acute endotoxin administration in conscious sheep.

We evaluated cardiac function in an unanesthetized ovine model of hyperdynamic endotoxemia. The animals were instrumented for crystallographic dimension analysis of the left ventricle (LV) and measurement of LV, aortic, atrial, central venous, and pulmonary arterial pressures, and cardiac output. Seven sheep received 1.5 micrograms/kg of Escherichia coli endotoxin [lipopolysaccharide (LPS) LPS-P group] and were compared to a sham group. The sham group demonstrated no significant change in any of the variables. In the LPS-P group, the cardiac index increased (5.7 +/- 0.4 to 7.9 +/- 0.6 l.min-1.m-2) between 8 and 12 h after LPS. Concomitantly, the maximum elastance of LV end-systolic pressure-volume relations significantly decreased (2.88 +/- 0.27 mmHg/ml) compared with baseline (3.89 +/- 0.50 mmHg/ml). Other indexes of the LV contractility (maximum pressure development and ejection fraction) were also reduced. There was a simultaneous increase in the LV end-systolic and diastolic volumes. These findings confirm the hypothesis that there is a myocardial depression during LPS in the ovine model.

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↗
PubMed1991

Cardiac function in an ovine model of endotoxemia.

Eight awake sheep were monitored with ultrasonic crystals, positioned at the anterior and posterior left ventricular wall. A left-sided intraventricular pressure transducer and a right ventricular ejection fraction catheter were positioned in the right and left hearts, respectively. After administration of endotoxin (Escherichia coli, LPS 1.5 micrograms/kg in 30 min), the hemodynamic variables showed a triphasic course. Phase I, (0-1 hr post LPS) was characterized by an increased pulmonary artery pressure and a decreased right ventricular ejection fraction. The inability of the right ventricle to compensate for the increased preload resulted in a fall of the left ventricular preload, stroke volume, and cardiac output. Three hours after LPS administration a second drop of the cardiac output was noted (phase II). This occurred as a result of a fall in preload. Eight hours post LPS a hyperdynamic phase (phase III) was distinguished, with a high cardiac output and a low systemic vascular resistance. During this time there was evidence of probable reduced myocardial contractility.

Animals↗
PubMed1991

Hyperdynamic sepsis in baboons: I. Aspects of hemodynamics.

The baboon has a number of advantages as a shock model, as its physiological as well as its biochemical behaviour is similar to man. Therefore we have tried to set up a model to mimic the early hyperdynamic phase of clinical sepsis. Seven baboons, 21-25 kg body weight were kept under EEG servocontrolled anesthesia for 8 hr. During this time live E. coli (ATC #33985) 2 x 10(10) BW/8 hr were continuously infused intravenously. Adequate fluid supply with Ringer's solution (up to 40 ml/kg/hr) was given to keep the pulmonary artery wedge pressure at baseline levels; this procedure resulted in a hyperdynamic response with a cardiac output (CO) 20-35% above baseline and a decrease (20-39%) in mean arterial pressure (MAP), leading to a 50% decrease in peripheral resistance. The pulmonary vascular changes were reflected in an increase of the mean pulmonary pressure (PA) to 42% above baseline and a marked rise in pulmonary vascular resistance (PVR) to 50% above baseline with no additional changes in pulmonary gas exchange. After 8 hr both CO and MAP were inversely correlated (r = 0.9-1) with dramatically increased catecholamine plasma levels (15 times above baseline). With continuous infusion of live E. coli (blood levels 10(5)-10(6) CFU/ml) and massive fluid supply we have successfully mimicked hyperdynamic sepsis with severe organ failure after an 8-hr observation period.

Animals↗
PubMed1990

Methodological approach to the characterization of diacylphosphatidyl cholines in rabbit lung lavage fluid by fast-atom bombardment mass spectrometry.

Strong evidence exists that the distribution of phospholipids in the lung is a function of the degree of adult respiratory distress syndrome. The capabilities of positive-ion fast-atom bombardment (FAB) mass spectrometry for the determination of the relative distribution of intact diacylphosphatidylcholine species in lung lavage fluid were investigated. Two different FAB matrices and two different isolation/purification procedures--extraction/thin layer chromatography--high performance liquid chromatography (TLC-HPLC)--have been evaluated. In addition the relative fatty acid composition of the diacylphosphatidylcholines was determined by negative-ion FAB mass spectrometry using the [RCOO]- fragment ion. These results were compared with those obtained by gas chromatographic determination of the fatty acid methylesters.

Animals↗