Effects of acute lipopolysaccharide-induced toxemia model on some neglected blood parameters.

The presence of lipopolysaccharide (LPS) in blood induces an inflammatory response which leads to multiple organ dysfunction and numerous metabolic disorders. Uncontrolled, improper or late intervention may lead to tissue hypoxia, anaerobic glycolysis and a disturbance in the acid -base balance. The effects of LPS-induced toxemia on biological and immunological markers were well studied. However, parameters such as base excess, ions, and acid-base balance were not fully investigated. Therefore, the objective of this study was to examine these blood parameters collectively in LPS-induced inflammatory toxemia in rat's model. After induction of toxemia by injecting LPS at a rate of 5 mg/kg body weight intravenously, blood was collected from the tail vein of twenty rats and immediately analyzed. After 24 hours, the animals were sacrificed and the blood was collected from the caudal vena cava. The results revealed that the levels of pH, bicar- bonate, partial pressure of oxygen, oxygen saturation, Alveolar oxygen, hemoglobin, hematocrit, magnesium (Mg2+), and calcium (Ca2+) were significantly decreased. On the other side, the levels of Base excess blood, Base excess extracellular fluid, partial pressure of carbon dioxide, lactate, Ca2+/Mg2+, potassium, and chloride were significantly increased compared to those found pre toxemia induction. However, sodium level showed no significant change. In conclusion, Acute LPS-toxemia model disturbs acid-base balance, blood gases, and ions. These parameters can be used to monitor human and animal toxemic inflammatory response induced by bacterial LPS conditions to assist in the management of the diagnosed cases.

Progressive toxemia with acetaldehyde in a reactive form of alcohol withdrawal syndrome.

We carried out a complex clinical and laboratory examination of 169 patients with reactive form of alcohol withdrawal syndrome. Progressive toxemia with acetaldehyde (key pathogenetic stage) and volemic changes were followed by homeostasis disorders and gradual decompensation of the natural detoxification system. The patients with this form of alcohol withdrawal syndrome did not exhibit physical and psychic dependence on alcohol. The proposed therapeutic algorithm for the treatment of various pathogenetic stages rapidly and efficiently restored homeostasis parameters and prevented the development of serious and life-threating complications.

Endotoxemia in rats is associated with induction of the P4504A subfamily and suppression of several other forms of cytochrome P450.

Bacterial lipopolysaccharide (LPS) has been previously shown to down-regulate the mRNA and protein expression of the hepatic cytochrome P450 (P450) isozymes 2C11 and 2C12. In this study, we examined the effects of LPS on the constitutive expression of P4503A2, P4502E1, and the P4504A subfamily in the rat. Fischer 344 and Sprague-Dawley rats were each administered 1 mg/kg LPS intraperitoneally and killed for hepatic RNA and microsome isolation at different times. LPS treatment was found to suppress P4502C11, P4503A2, and P4502E1 protein and mRNA expression in both strains of rat. Total microsomal P450 levels decreased by 30%, which was smaller than the effects on the levels of individual isozymes. The magnitude of suppression exhibited in the Sprague-Dawley rats, however, seemed to be more variable than that in the F344 strain. The mRNAs of all three of the P4504A subfamily members were induced 2- to 6-fold in the F344 rat livers after LPS administration. P4504A3 protein expression increased 2-fold, whereas P4504A1/2 protein levels decreased by 30%. Lauric acid omega-hydroxylase activity increased 1.6-fold in LPS-treated Fischer 344 rats and omega-1-hydroxylase activity decreased by 38%. In the Sprague-Dawley strain, however, decreases were seen in both omega- and omega-1-hydroxylase activities after LPS treatment. Our data demonstrate that LPS administration induces P4504A subfamily mRNA and P4504A3 protein expression. Furthermore, our findings also suggest strain differences in both suppression and induction of P450s between the Sprague-Dawley and F344 rats.

Interleukin 10 release during endotoxaemia in chimpanzees: role of platelet-activating factor and interleukin 6.

Interleukin (IL-)10 has been demonstrated to inhibit endotoxin-induced production of a number of pro-inflammatory cytokines. The present study sought to compare the appearances in the circulation of IL-10, IL-6 and IL-8, and to assess the roles of endogenously produced platelet-activating factor (PAF) and IL-6 in IL-10 release during endotoxaemia in chimpanzees. Intravenous injection of endotoxin (lot EC-5, 4 ng/kg, n = 8) induced a transient rise in serum IL-10 concentrations, peaking after 2 h (213 +/- 70 pg/ml; P < 0.05). No correlations existed between peak IL-10 levels, and peak IL-6 and IL-8 levels. Neither infusion of the specific PAF antagonist TCV-309 (n = 4), nor infusion of a neutralizing anti-IL-6 monoclonal antibody (n = 4) influenced endotoxin-induced IL-10 release. IL-10 release elicited by injection of endotoxin is not mediated by PAF or IL6.

Increased neutrophil respiratory burst in bcr-null mutants.

Philadelphia (Ph)-positive leukemias invariably contain a chromosomal translocation fusing BCR to ABL. The BCR-ABL protein is responsible for leukemogenesis. Here we show that exposure of bcr-null mutant mice to gram-negative endotoxin led to severe septic shock and increased tissue injury by neutrophils. Neutrophils of bcr (-/-) mice showed a pronounced increase in reactive oxygen metabolite production upon activation and were more sensitive to priming stimuli. Activated (-/-) neutrophils displayed a 3-fold increased p21rac2 membrane translocation compared with (+/+) neutrophils. These results connect Bcr in vivo with the regulation of Rac-mediated superoxide production by the NADPH-oxidase system of leukocytes and suggest a link between Bcr function and the cell type affected in Ph-positive leukemia.

Defective pulmonary recruitment of neutrophils in a rat model of endotoxemia.

We have characterized a defect in the pulmonary recruitment of neutrophils (PMNs) in rats with experimental endotoxemia. Rats pretreated with intravenous (IV) 0.9% saline (NaCl) showed abundant PMNs in bronchoalveolar lavage (BAL) fluid after intratracheal (IT) lipopolysaccharide (LPS) (5 mg/kg) (54.27 +/- 9.80 x 10(6), n = 7, versus IT saline, 0.73 +/- 0.62 x 10(6), n = 4). In contrast, endotoxemic rats (IV LPS 1.0 mg/kg) failed to show PMN influx after IT LPS (0.40 +/- 0.13 x 10(6) PMNs in BAL fluid, n = 7). Four hours after the IT administration of LPS, the chemotactic activity of BAL fluid from endotoxemic rats (87 +/- 9.92% of maximal chemotaxis toward zymosan-activated serum [ZAS], n = 4) was not significantly different (P > 0.05), from rats pretreated with IV NaCl (61.09 +/- 6.17% of maximal chemotaxis toward ZAS, n = 4). Endotoxemic and control rats showed similar chemotactic gradients in determinations of the BAL/plasma chemotactic activity ratio (BAL/plasma ratio: 2.16 +/- 0.14, n = 4, IV NaCl versus 2.98 +/- 0.14, n = 4, IV LPS, P > 0.05). Serum from untreated rats, rats pretreated with IV NaCl, and endotoxemic rats caused minimal effects on rat PMN chemotaxis in vitro (78.17 +/- 8.16%, 79.29 +/- 7.09%, and 69.28 +/- 9.04% of maximal chemotaxis toward ZAS, respectively, n = 4/group, P > 0.05). Quantitation of PMN adhesion molecules revealed a loss of L-selectin (8 +/- 5% of control group, n = 3), an increase in Mac-1 (776 +/- 82.60% of control group, n = 3), and no change in LFA-1 when normal PMNs were incubated with plasma from rats pretreated with IV LPS (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

[Experimental study on compatible application of heat-clearing and detoxifying drugs with blood circulation improving drugs].

The article describes the effectiveness of compatible application of heat-clearing and detoxifying drugs with blood circulation improving drugs to the animal model with endotoxemia and nonspecific inflammation. The compatible application reduces PGE2, endotoxin blood concentration and reduced viscosity of whole blood, decreases Evans blue extravasation volume and pes swelling percentage, increases serum cortisol content and enhances fibrinolytic activity. The experimental result shows that in most cases these two drugs work better when used in combination which implies that compatible application is more effective in detoxification, antiinflammation and inflammation recovery.

Simultaneous analysis of multiple cytokine receptor mRNAs by RNase protection assay in LPS-induced endotoxemia.

In order to examine the regulation of cytokine receptor gene expression an RNase protection assay (RPA) was developed that allows the simultaneous and semiquantitative measurement of mRNAs encoding for the IL-1 p60 and p80, TNF p55 and p75, IFN-gamma, and IL-6 receptors. Titration experiments revealed that this method was very sensitive allowing the detection of the target cytokine receptor mRNAs down to at least 0.01 microgram of spleen poly(A)+ RNA. The cytokine receptor RPA was used to examine the expression of the receptor genes in various organs from normal mice and mice that had been injected with LPS. In normal mice expression of the IL-1R p80, TNFR p55 and p75, IFN-gamma, and IL-6R but not the IL-1R p60 transcripts was readily detectable in spleen, liver, kidney, and brain. Following LPS treatment, there was an induction of the IL-1R p60 mRNA in all organs and an up-regulation of the IL-1R p80, TNFR p55 and p75, IFN-gamma, and IL-6 receptor mRNAs particularly in spleen, liver, and kidney. Interorgan differences were observed in the regulation of these receptor mRNAs, indicating an organ-specific response to the LPS challenge. Our findings indicate the cytokine receptor RPA is a powerful and versatile tool for the simultaneous analysis of multiple cytokine receptor mRNAs in tissue samples. This technique will prove valuable in further evaluating the coordinated regulation of the expression of these genes, which are pivotal in the biology of cytokines.(ABSTRACT TRUNCATED AT 250 WORDS)

Octreotide does not alter endotoxin lethality in mice or endotoxin-induced suppression of human leukocyte migration.

Octreotide, a somatostatin analog, was evaluated for its effects on long-term survival in a mouse model of endotoxemia and for its effects on endotoxin-induced suppression of human leukocyte migration. Swiss Webster mice were simultaneously rendered endotoxemic with a single intraperitoneal injection of 800 micrograms E. coli Lipopolysaccharide (LPS) and treated with one of four doses of subcutaneous (s.c.) octreotide (1.0 mg/kg in 0.4 ml saline, 0.1 mg/kg in 0.4 ml saline, 0.1 mg/kg in 0.04 ml saline, or 0.001 mg/kg in 0.04 ml saline) or saline alone (fluid-resuscitated control group: 0.4 ml saline s.c.; or non-fluid-resuscitated control group: 0.04 ml saline s.c.). Octreotide was continued with or without supplemental s.c. fluid resuscitation (0.4 ml saline) at eight hour intervals for either twenty-four or forty hours. There was no statistical significance to differences in long-term survival between comparable groups of octreotide treated vs saline treated animals during the entire fourteen day period of observation. Fluid resuscitation during the first forty hours following endotoxemia induction delayed death, but did not significantly improve long-term survival. In vitro work was conducted to determine the effect of octreotide on endotoxin-induced suppression of human leukocyte migration. Octreotide at concentrations ranging from 3.05 x 10(-5) Molar to 3.05 x 10(-11) Molar had no significant effect on leukocyte migration. In this study octreotide treatment failed to improve long-term survival in mice with endotoxemia and did not alter endotoxin-induced suppression of leukocyte migration.

Environmental pollutants in relation to complications of pregnancy.

Certain complications of pregnancy, e.g., threatened spontaneous abortion, toxemia, emesis, and anemia, were studied in pregnant women living in industrial areas contaminated by smelters and the petrochemical industry. Exposure to lead or aromatic hydrocarbons was assessed in parallel by the determination of these agents or their metabolites in blood and urine. Comparison of respective exposure levels was made between women with normal pregnancies and those with complications. Significantly higher levels of lead in blood and increased excretion of the metabolic products of organic solvents were found in women with complicated pregnancies compared to those with normal pregnancies. Threatened spontaneous abortion, toxemia, and anemia were associated with higher lead exposure in the vicinity of smelters. In these patients, evidence of disturbances of blood glutathione equilibrium and increased lipid peroxidation were found indicating a decreased ability to compensate for the effects of exposure. Styrene exposure in a petrochemical industrial area was associated mainly with late toxemia and nephropathy. Patients with these complications also had a tendency to elevated exposure to other aromatic hydrocarbons. It is suggested that complications of pregnancy may be induced by environmental agents at levels lower than those that result in pregnancy loss or preterm birth.

Regulation of tumor necrosis factor-alpha receptors on macrophages: differences between primary macrophages and transformed macrophage cell lines.

Macrophages are a pivotal cell in the production of a variety of cytokines. In addition, macrophages express receptors on their surface which allows them to act as target cells for cytokines. The regulation of both cytokine production and cytokine receptor expression in macrophages may play a key role in modulating the processes of inflammation, injury, and repair. In this report we have studied the regulation of macrophage receptors for tumor necrosis factor-alpha (TNF alpha) on rat bone marrow-derived macrophages, rat alveolar macrophages, human monocyte-derived macrophages, and the human monocyte-like cell line, U937, by a variety of immunomodulatory and inflammatory agents. U937 cells and rat and human macrophages bound TNF alpha in a saturable process, with an affinity in each cell type of approximately 1 nM. Following incubation with phorbol myristate acetate for 60 min, TNF alpha binding to all cells was decreased. Interleukin-1 treatment increased TNF alpha binding to human and rat macrophages. Interferon-gamma treatment decreased receptor activity in both human and rat macrophages, but increased TNF alpha binding to U937 cells. Treatment of human and rat macrophages with endotoxin resulted in a rapid loss of TNF alpha binding, while endotoxin treatment increased receptor expression in U937 cells. In all cases, receptor regulation was the result of a change in receptor number. Finally, following intraperitoneal injection of endotoxin, TNF alpha receptor expression was down-regulated on alveolar lavage cells from rats.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pulmonary microcirculatory changes in acute lung injury in rats induced by burns and endotoxin administration].

An animal model of acute pulmonary injury similar to adult respiratory distress syndrome (ARDS) was produced by intravenous injection of E. coli endotoxin to burned rats. The changes in pulmonary microcirculation were observed in vivo with "pleura window" method and the cast of the lung capillaries was studied using scanning electron microscope. The histological changes in the lung in these rats were observed with transmission electron microscope. It was shown that lung vessels constricted, microvascular permeability increased, pulmonary edema occurred and leukocytes and aggregated platelets accumulated in lung capillaries. This study suggested that pulmonary microcirculatory changes are the pathological basis of acute lung injury induced by burns accompanied with endotoxemia.

Effect of inhibition of 5-lipoxygenase metabolism of arachidonic acid on response to endotoxemia in sheep.

We studied the effects of a 5-lipoxygenase inhibitor, L-651,192, on the pulmonary dysfunction caused by endotoxemia in chronically instrumented unanesthetized sheep. The efficacy and selectivity of L-651,392 were tested by measuring in vivo production of leukotriene B4 (LTB4) and cyclooxygenase products of arachidonic acid after endotoxemia before and after pretreatment with L-651,392 and ex vivo from granulocytes and whole blood stimulated with calcium ionophore from sheep before and 24 h after pretreatment with L-651,392. A novel assay for LTB4 by high-performance liquid chromatography/gas chromatography/mass spectrometry techniques was developed as a measure of 5-lipoxygenase metabolism of arachidonic acid. L-651,392 proved to be an effective in vivo 5-lipoxygenase inhibitor in sheep. L-651,392 blocked the increase in LTB4 observed in lung lymph after endotoxemia in vivo in sheep as well as inhibited by 80% the ex vivo production of LTB4 by granulocytes removed from sheep treated 24 h earlier with L-651,392. Although L-651,392 blocked the increase in cyclooxygenase products of arachidonic acid observed in lung lymph after endotoxemia in vivo in sheep, the drug probably did not function directly as a cyclooxygenase inhibitor. L-651,392 did not attenuate the ex vivo production of thromboxane B2 by whole blood from sheep treated 24 h earlier with the drug. L-651,392 attenuated the alterations in pulmonary hemodynamics, lung mechanics, oxygenation, and lung fluid and solute exchange observed after endotoxemia in sheep. We speculate that 5-lipoxygenase products are a major stimulus for cyclooxygenase metabolism of arachidonic acid after endotoxemia in sheep.

Dose-dependent effects of a pyridoquinazoline thromboxane synthetase inhibitor on arachidonic acid metabolites and hemodynamics during E. coli endotoxemia in anesthetized sheep.

We investigated the effects of a new pyridoquinazoline thromboxane synthetase inhibitor infused before administering Escherichia Coli endotoxin into 18 anesthetized sheep with lung lymph fistulas. In normal sheep increasing plasma Ro 23-3423 concentrations were associated with increased plasma levels of 6-keto-PGF1 alpha, a reduced systemic vascular resistance (SVR, r = -0.80) and systemic arterial pressure (SAP, r = -0.92), the mean SAP falling from 80 to 50 mm Hg at the 20 and 30 mg/kg doses. Endotoxin infused into normal sheep caused transient pulmonary vasoconstriction associated with increased TxB2 and 6-keto-PGF1 alpha levels while vasoconstriction and TxB2 increase were significantly inhibited by pretreatment with Ro 23-3423 in a dose-dependent manner. When compared to controls, plasma and lymph levels of 6-keto-PGF1 alpha, PGF2 alpha and PGE2 after endotoxin infusion were increased several-fold by administering Ro 23-3423 up to plasma levels of 10 micrograms/ml. Doses over 30 mg/kg with blood levels above 10 micrograms/ml reduced plasma and lymph levels of 6-keto-PGF1 alpha, PGF2 alpha and PGE2, suggesting cyclooxygenase blockade at this dose. The peak 6-keto-PGF1 alpha levels at 60 min after endotoxin infusion in sheep with Ro-23-3423 levels below 10 micrograms/ml were associated with the greatest systemic hypotension due to a reduced SVR (r = -0.86). After endotoxin infusion the leukotrienes B4, C4, D4 and E4 in lung lymph were assayed by radioimmunoassay and high pressure liquid chromatography and remained at baseline values.

Clotting and other plasma factors in experimental endotoxemia: inhibition of degradation by exogenous proteinase inhibitors.

Endotoxemia in dogs was induced by a slow intravenous infusion of E. coli endotoxin for 2 h. Thereby, a significant decrease was observed in the plasma levels of several clotting, fibrinolysis and complement factors. The changes were studied over an experimental period of 14 h and checked for statistical significance by three-way analysis of variance. Application of the broad-spectrum proteinase inhibitor aprotinin (Trasylol) from bovine organs clearly lowered the endotoxin-induced decline of the plasma proteins studied. By intravenous application of a specific granulocytic proteinase inhibitor (Bowman-Birk inhibitor from soybeans), the endotoxin-induced reduction of the plasma proteins was prevented in a similar manner. It can be concluded that at least some of the pathobiochemical mechanisms observed in clotting, fibrinolysis and complement systems during endotoxemia are not only caused by a severe consumption reaction but also by unspecific proteolytic degradation due to neutral granulocytic proteinases.

Albumin shifts across the extracellular space secondary to experimental infections.

The pathway across tissue spaces of intravenously injected 125I albumin was studied in five dogs before and after the injection of Escherichia coli endotoxin by the use of perforated plastic capsules placed in the subcutaneous tissue. The already negative extracellular space pressure became less so after the endotoxin injection, when albumin was detected shifting from the intravascular space into the extracellular space compartment and then into the intralymphatic space. The injection of endotoxin produced a marked increase in the thoracic duct lymph flow, while, at the same time, erythrocytes entered the lymphatic stream. Results of this study suggest that experimental canine endotoxemia is associated with an increased passage of albumin into the extravascular compartment and explains, in part, the fall in serum levels of this protein during clinical and experimental sepsis.