Coli Sepsis Research Articles

POSSIBLE ROLE OF TNF ON PROCALCITONIN RELEASE IN A BABOON MODEL OF SEPSIS

Procalcitonin (PCT) has been described as an early and discriminating marker of bacteria-associated sepsis in patients. However, little is known of its source and actions, especially with regard to its relation to tumor necrosis factor (TNF). TNF is responsible for the release of several other mediators of sepsis e.g., chemokines. We tested the hypothesis that plasma PCT levels during sepsis differ with regard to the degree of TNF availability. Severe hyperdynamic sepsis was induced in baboons (n = 14) by i.v. infusion of live E. coli (approximately 2 x 10(9) colony-forming units/kg) over 2 h. Animals were pretreated 2 h before E. coli either with 1 mg/kg humanized anti-TNF antibody (CDP571) or placebo (Ringer solution). Plasma PCT levels at baseline was barely detectable, but increased to about 4000 pg/mL at 4 h after E. coli infusion. Levels were maximal between 8 and 24 h and had returned nearly to baseline at 72 h. Although no TNF could be measured in the treated group, PCT levels were not different between the placebo and the TNF antibody treatment group. We conclude that PCT levels are not dependent on the systemic presence of TNF in an E. coli sepsis model in baboons. Such sepsis induced PCT release is clearly different from the previously reported PCT release during infusion of rhTNF in volunteers or chimpanzees.

Escherichia coli sepsis increases hepatic apolipoprotein B secretion by inhibiting degradation.

Sepsis leads to hypertriglyceridemia in both humans and animals. Previously, we reported that plasma very low density lipoprotein apolipoprotein (apo) B and hepatic production of apoB increased during Escherichia coli sepsis. The present experiments were undertaken to determine whether the altered hepatic secretion of apoB was associated with an increase in synthesis or a decrease in degradation rate. Sepsis was induced in male, Lewis rats (225-275 g) by intravenous injection of 3.8 x 10(8) live E. coli colonies/100 g body. Twenty-four hours later rats were sacrificed, and primary hepatocytes were prepared and incubated overnight with 35S-methionine. Hepatocytes from E. coli-treated rats secreted twice as much apoB-48 and total apoB than the hepatocytes from control rats. Escherichia coil sepsis increased cellular triglyceride mass by 86%, which was due to a stimulation in triglyceride synthesis from newly synthesized fatty acids, measured by 3H2O incorporation into triglycerides. The apoB synthesis rate, apoB mRNA levels, and apoB mRNA editing were not altered during E. coil sepsis. The pulse-chase experiments showed that the rate of apoB degradation decreased in E. coli-treated rats. These findings demonstrate that the secretion of apoB is regulated posttranslationally during E. coli sepsis by decreasing the degradation of newly synthesized apoB, which contributes to the development of hypertriglyceridemia.

Lincomycin-induced endotoxin release in Escherichia coli sepsis: evidence for release in vitro and in vivo

Objective: To evaluate the propensity of lincomycin and clindamycin to induce release of endotoxin, the authors investigated endotoxin release in Escherichia coli isolated from a patient who developed septic shock following lincomycin treatment. Methods: Endotoxin release from the E. coli isolate exposed to lincomycin, clindamycin, and ceftazidime were determined in vitro and in vivo. Results: In vitro, this E. coli released significantly larger amounts of endotoxin after exposure for 6 hours to lincomycin or clindamycin versus no antibiotic; however, endotoxin release with these antibiotics was significantly less than with ceftazidime. There was no significant difference in in vitro endotoxin release between small (8 mg/L) and large (0.5 minimum inhibitory concentration [MIC]) doses of these antibiotics, and 0.5 MICs of lincomycin and clindamycin were 1024 and 256 mg/L, respectively. These results were supported by scanning electron microscopic observations, which demonstrated that lincomycin, clindamycin, and ceftazidime induced formation of filamentous cells. In addition, plasma endotoxin concentrations after treatment for 4 hours with lincomycin, clindamycin, and ceftazidime (5 mg/kg) were at least 20-fold higher than with no antibiotic in an E. coli sepsis rat model. Conclusion: Results of this study suggest that the bacteriostatic antibiotics, lincomycin and clindamycin, induce endotoxin release in the treatment of E. coli infections.

Complement component C9 enhances the capacity of beta-lactam antibiotics to kill Escherichia coli in vitro and in vivo.

Complement component C9 is required for rapid complement-mediated killing of Escherichia coli. In this report, the influence of supplemental C9 on the bactericidal and protective effects of beta-lactam antibiotics in neonates was assessed. By rocket immunoelectrophoresis, the intrinsic C9 concentrations of pooled serum from both human and rat neonates was less than 20% of adult levels. Supplemental C9 purified from human plasma enhanced the capacity of ampicillin-treated serum from human neonates to impair the survival of E coli O7:K1:NM (P < 0.02). Similarly, supplemental C9 enhanced the capacity of cefotaxime-treated neonatal rat serum to impair the survival of E coli O1:K1:NM (P < 0.05). Moreover, the intraperitoneal administration of C9 enhanced the survival of cefotaxime-treated neonatal rats that were septic with E coli (P < 0.05). These observations may contribute to the development of new strategies, such as augmentation of complement component serum concentrations, to reduce the morbidity and mortality of neonatal E coli sepsis.

Complement Component C9 Enhances the Capacity of Beta-Lactam Antibiotics to Kill Escherichia coli In Vitro and In Vivo

Complement component C9 is required for rapid complement-mediated killing of Escherichia coli. In this report, the influence of supplemental C9 on the bactericidal and protective effects of beta-lactam antibiotics in neonates was assessed. By rocket immunoelectrophoresis, the intrinsic C9 concentrations of pooled serum from both human and rat neonates was less than 20% of adult levels. Supplemental C9 purified from human plasma enhanced the capacity of ampicillin-treated serum from human neonates to impair the survival of E coli O7:K1:NM (P < 0.02). Similarly, supplemental C9 enhanced the capacity of cefotaxime-treated neonatal rat serum to impair the survival of E coli O1:K1:NM (P < 0.05). Moreover, the intraperitoneal administration of C9 enhanced the survival of cefotaxime-treated neonatal rats that were septic with E coli (P < 0.05). These observations may contribute to the development of new strategies, such as augmentation of complement component serum concentrations, to reduce the morbidity and mortality of neonatal E coli sepsis.

Recombinant Antitrypsin Pittsburgh Undergoes Proteolytic Cleavage during E. coli Sepsis and Fails to Prevent the Associated Coagulopathy in a Primate Model

During severe sepsis there is dramatic activation of both contact proteases and the coagulation pathway. These processes contribute to the development of shock and disseminated intravascular coagulation (DIC) respectively. The Pittsburgh mutant of antitrypsin (358Met-Arg) is a novel protease inhibitor with activity against both thrombin and the contact proteases and should therefore prove beneficial as a therapeutic agent in the management of septic shock. This hypothesis was supported by an earlier study in a pig model where recombinant antitrypsin Pittsburgh (rAT Pittsburgh) at a concentration of 1 microM alleviated some of the features of shock, but did not improve survival. In order to reduce the lethal effects of E. coli sepsis we postulated that a higher concentration of antitrypsin Pittsburgh would be necessary. To test this hypothesis we used rAT Pittsburgh in a primate model. This was chosen in preference to another species as E. coli sepsis in the primate has been well characterised and closely resembles the changes seen in man. Surprisingly this treatment did not alleviate the features of shock and unexpectedly appeared to exacerbate the associated coagulopathy. We propose two possible mechanisms for this unforeseen outcome. The first results from the broad spectrum of activity of antitrypsin Pittsburgh. As well as inhibiting thrombin and the contact proteases, the Pittsburgh mutant also inhibits activated protein C. Inhibition of the protein C system is known to exacerbate septic shock. Secondly, a significant quantity of inactive antitrypsin Pittsburgh, cleaved at the reactive centre, was detected in the plasma of the treated animals. Proteolytically altered serpins, including antitrypsin. have been shown to enhance the inflammatory process. Therefore the accumulation of cleaved rAT Pittsburgh might be expected to exacerbate septic shock.

Cardiopulmonary effects of inhaled nitric oxide in normal dogs and during E. coli pneumonia and sepsis.

We investigated the effect of inhaled nitric oxide (NO) at increasing fractional inspired O2 concentrations (FIO2) on hemodynamic and pulmonary function during Escherichia coli pneumonia. Thirty-eight conscious, spontaneously breathing, tracheotomized 2-yr-old beagles had intrabronchial inoculation with either 0.75 or 1.5 x 10(10) colony-forming units/kg of E. coli 0111:B4 (infected) or 0.9% saline (noninfected) in one or four pulmonary lobes. We found that neither the severity nor distribution (lobar vs. diffuse) of bacterial pneumonia altered the effects of NO. However, in infected animals, with increasing FIO2 (0.08, 0.21, 0.50, and 0.85), NO (80 parts/million) progressively increased arterial PO2 [-0.3 +/- 0.6, 3 +/- 1, 13 +/- 4, 10 +/- 9 (mean +/- SE) Torr, respectively] and decreased the mean arterial-alveolar O2 gradient (0.5 +/- 0.3, 4 +/- 2, -8 +/- 7, -10 +/- 9 Torr, respectively). In contrast, in noninfected animals, the effect of NO was significantly different and opposite; NO progressively decreased mean PO2 with increasing FIO2 (2 +/- 1, -5 +/- 3, -2 +/- 3, and -12 +/- 5 Torr, respectively; P < 0.05 compared with infected animals) and increased mean arterial-alveolar O2 gradient (0.3 +/- 0.04, 2 +/- 2, 1 +/- 3, 11 +/- 5 Torr; P < 0.05 compared with infected animals). In normal and infected animals alike, only at FIO2 < or = 0.21 did NO significantly lower mean pulmonary artery pressure, pulmonary artery occlusion pressure, and pulmonary vascular resistance index (all P < 0.01). However, inhaled NO had no significant effect on increases in mean pulmonary artery pressure associated with bacterial pneumonia. Thus, during bacterial pneumonia, inhaled NO had only modest effects on oxygenation dependent on high FIO2 and did not affect sepsis-induced pulmonary hypertension. These data do not support a role for inhaled NO in bacterial pneumonia. Further studies are necessary to determine whether, in combination with ventilatory support, NO may have more pronounced effects.

Disturbance of energy metabolism in acute septic cardiomyopathy: decreased activities of the complexes I and II of the mitochondrial respiratory chain and phosphofructokinase

Acute septic cardiomyopathy accounts for about 10% of fatalities in sepsis and septic shock. Currently, therapy of septic cardiomyopathy is merely symptomatic. Causal therapeutic approaches could help reduce mortality. In the skeletal muscle of septic patients elevated oxygen partial pressures have been detected indicating a diminished oxygen consumption of mitochondria in sepsis. There is evidence that tumor necrosis factor α and interleukin 1 disturb mitochondrial function of cardiomyocytes in vitro. It was therefore assumed that mitochondrial function in septic cardiomyopathy may be disturbed. Ten key enzymes of energy metabolism were determined in vitro in myocardial tissue (removed post mortem) of septic and non-septic (sham) baboons under systemic anaesthesia, a standardised and hemodynamically well-characterised model of E coli sepsis. Measurements were performed spectrophotometrically and enzyme activities referred to non-collagen protein (NCP) (mU/g NCP, mean ± SEM). A newly developed principal component analysis of data was used to detect impaired enzyme pattern in myocardial specimen. Two sepsis protocols were compared: single challenge and multiple challenge (less E coli). A 50% reduction of the activity of complex II of the respiratory chain was found after single challenge (3.6 ± 0.6) in comparison to the multiple challenge group (7.3 ± 2.1, P < 0.05). The other enzymes were less affected. The activities of the complexes I and II and phosphofructokinase were significantly lowered after single challenge in the heart in lethal septic shock (I), in comparison to non-lethal septic shock (II) and to the sham animals *P < 0.05). The effects on cytochrome-c-oxidase, succinate dehydrogenase and complex III were essentially smaller, and citrate synthase was nearly unaffected. Similar changes were observed after multiple challenge protocol too.

High-dose recombinant endotoxin neutralizing protein improves survival in rabbits with Escherichia coli sepsis

To assess the benefit of a recombinant endotoxin neutralizing protein from Limulus polyphemus in treating Gram-negative bacterial sepsis in rabbits. Prospective, blinded, controlled, laboratory trial. Animal research laboratory. New Zealand White rabbits. We established a rabbit model of Escherichia coli peritonitis and bacteremia, with high mortality rate, despite treatment with gentamicin and ceftriaxone. Twenty-five pairs of male New Zealand White rabbits were challenged intraperitoneally with E. coli O18ac K1 in 5% porcine mucin (mean 7 x 10(1) colony-forming units). All animals were treated with intravenous gentamicin (2.5 mg/kg) and ceftriaxone (100 mg/kg), and with either intravenous endotoxin neutralizing protein (50 mg/kg) or saline 1 hr after E. coli challenge. All animals were bacteremic 1 hr after challenge (mean 3.6 x 10(5) colony-forming units/mL). Animals in both groups developed tachycardia, hypotension, and acidosis (NS). Geometric mean serum endotoxin and tumor necrosis factor (TNF) concentrations were significantly ( p < .001) higher 1 hr after challenge compared with baseline prechallenge concentrations in both groups. From 1 to 2 hrs after challenge, endotoxin concentrations increased 2.5-fold in control animals (95% confidence interval = 13.1 to 32.9 endotoxin units/mL, p = .024), whereas endotoxin concentrations increased only 1.2-fold in endotoxin neutralizing protein-treated animals (95% confidence interval = 20.4 to 23.6 endotoxin units/mL, NS). TNF concentrations increased significantly (p < .001) in both groups from 1 to 2 hrs after challenge. Eighteen (72%) of 25 endotoxin neutralizing protein-treated animals vs. 11 (44%) of 25 controls survived 24 hrs (p = .032). Treatment with endotoxin neutralizing protein had the following effects: a) the increase in serum endotoxin was blunted, but not TNF concentrations measured 1 hr after antibiotic treatment; and b) survival in rabbits with E. Coli sepsis was improved.

Growth hormone and insulinlike growth factor I enhance host defense in a murine sepsis model.

To investigate the effects of exogenous growth hormone (GH) and insulinlike growth factor I (IGF-I) on host defense and survival in a murine model of Escherichia coli sepsis. Prospective randomized experimental trials. Laboratory. Nine-week-old female BALB/c mice. Mice were injected subcutaneously with 4.8 or 0.48 mg/kg of body weight per day of GH, 24 or 2.4 mg/kg of body weight per day of IGF-I or, as a control, normal saline solution, for 6 days. Mice were then challenged intraperitoneally with 1 x 10(8) colony-forming units per body of E coli. Fifty mice were observed for survival. In the next experiments, samples from the high-dose GH, high-dose IGF-I, and saline control groups were harvested before or at 4 or 6 hours after challenge. Numbers of peritoneal exudative cells and tissue-viable bacterial counts were determined. Peritoneal exudative cells were cultured with lipopolysaccharide (10 micrograms/mL) for 24 hours. Levels of tumor necrosis factor, interleukin-1, and interleukin-6 in the peritoneal lavage fluid, plasma and supernatants of peritoneal exudative cell culture were measured. Both high and low doses of GH and high-dose IGF-I significantly prolonged survival. Growth hormone and IGF-I significantly increased peritoneal exudative cell numbers and reduced viable bacterial counts in the peritoneal lavage fluid and the liver. These hormones significantly suppressed excessive systemic cytokine production, while enhancing in vitro cytokine production and preserving local cytokine responses. The immunomodulation produced by administration of GH or IGF-I leads to improved host defense in this murine model of E coli sepsis.

Cutaneous malacoplakia

Indurated, erythematous plaques of the left arm and left flank developed in a 69-year-old white man with multiorgan failure from Escherichia coli sepsis. Cutaneous malacoplakia was diagnosed. Intravenous antibiotic therapy resulted in resolution of the malacoplakia and the E. coli sepsis.

In vitro effects of in vivo activated leukocytes on RBC filterability and lipid peroxidation

Activated leukocytes are known to generate reactive oxygen species which may attack other cells in their surroundings. On the other hand, rheological properties of red blood cells (RBC) are atIected by oxidant attack. This study was designed to detetmine the intluence of activated leukocytes on RBC rheology in vitro. Activated leukocytes were isolated from the Guinea pigs with an induced E. Coli sepsis and incubated with RBC obtained from normal animals. After two hours of incubation with activated leukocytes, RBC deform ability indices were increased 1.23 ± 0.05 (Mean±Standart error) times (compared to the control RBC suspensions) while incubation with leukocytes obtained from healthy animals increased defOlmability indices 1.12 ± 0.03 times. Thiobarbituric acid reactive substances as a measure of lipid peroxidation were increased 2.95 ± 0.36 times in the RBC suspensions incubated with activated leucocytes, but 1.70 ± 0.10 times in suspensions incubated with nOlmal leukocytes. These results suggest that RBC mechanical properties might be affected by activated leukocytes and possibly an oxidative mechanism plays role in this interaction.

32 EVALUATION OF TOLOZOLINE TEST IN THE TREATMENT OF PERSISTENT PULMONARY HYPERTENSION OF THE NEWBORN (PPHN) BY DOPPLER ECHOCARDIOGRAPHY

To reverse pulmonary hypertension and to improve hypoxemia in PPHN, tolazoline (TZ) was tested to assess its ability to decrease pulmonary resistances. We aim to study the response to TZ vasodilation by Doppler echocardiography. We sequentially studied profiles of blood velocities in the left pulmonary artery. Through the second intercostal space, the zero angle incidence beam with the LPA allows reproducibility of repeated measurements. The ductal flow was recorded arid gradient calculated. After baseline, TZ bolus infusion was started at 1 mg/kg for 15 min, then increased by steps of 1 mg/kg if no response. Measurements were done every 5 min during the test. Material: The cohort included seven cases of PPHN:Diaphragmatic hernia, respiratory distress syndrome, Strepto, Coli and Mycoplasma sepsis. Results: the different responses were I-Immediate increased pulmonary blood flow and increase in PaO2, 2-TZ dose dependent increased PBF, 3-immediaic increase in flow and deferred increase in PaO2, 4 -Absence of response. In conclusion, Doppler evaluation of PBF, during TZ infusion, demonstrates immediate response on PBF allowing dose adaptation. It also demonstrates the magnitude of reversed shunt across the ductus to increase diastolic PBF. Transductal gradient gives estimation of pulmonary arterial pressure. It shows presence of intrapulmonary right to left shunt and evidence of hypoventilation. Then increased doses of TZ leading to ominous side-effects are avoided.

DEGR-Factor Xa Blocks Disseminated Intravascular Coagulation Initiated by Escherichia coli Without Preventing Shock or Organ Damage

One of the aims of research in the area of thrombosis has been to design an effective anticoagulant that would function in a predictable and direct manner. In evaluating the role of coagulation in sepsis we used factor Xa blocked in the active center with [5-(dimethylamino)1-naphthalenesulfonyl]-glutamylglycylarginyl+ ++ chloromethyl ketone (DEGR-Xa). We infused 1 mg/kg of DEGR-Xa together with LD100 concentrations of Escherichia coli (4 x 10(10) organisms/kg) into five baboons. As controls, we infused E coli alone into five baboons. The inflammatory, coagulant, and cell injury responses to E coli of both the treated and control groups were lethal and were similar in every respect except for the complete inhibition of the consumption of fibrinogen in the DEGR-Xa group. The half life of DEGR-Xa was approximately 10 hours and 2 hours, as determined by isotopic and enzyme-linked immunosorbent assays, respectively. These results for the first time demonstrate that, although coagulation occurs in E coli sepsis, fibrin formation per se did not influence the lethal outcome in this model. These results also show the effectiveness of DEGR-Xa as an anticoagulant and raise the possibility that it could serve as an alternative to anticoagulants currently in use.

DEGR-factor Xa blocks disseminated intravascular coagulation initiated by Escherichia coli without preventing shock or organ damage

One of the aims of research in the area of thrombosis has been to design an effective anticoagulant that would function in a predictable and direct manner. In evaluating the role of coagulation in sepsis we used factor Xa blocked in the active center with [5-(dimethylamino)1- naphthalenesulfonyl]-glutamylglycylarginyl+ ++ chloromethyl ketone (DEGR-Xa). We infused 1 mg/kg of DEGR-Xa together with LD100 concentrations of Escherichia coli (4 x 10(10) organisms/kg) into five baboons. As controls, we infused E coli alone into five baboons. The inflammatory, coagulant, and cell injury responses to E coli of both the treated and control groups were lethal and were similar in every respect except for the complete inhibition of the consumption of fibrinogen in the DEGR-Xa group. The half life of DEGR-Xa was approximately 10 hours and 2 hours, as determined by isotopic and enzyme-linked immunosorbent assays, respectively. These results for the first time demonstrate that, although coagulation occurs in E coli sepsis, fibrin formation per se did not influence the lethal outcome in this model. These results also show the effectiveness of DEGR-Xa as an anticoagulant and raise the possibility that it could serve as an alternative to anticoagulants currently in use.

Multiple small bowel perforations in leukemia secondary to epstein-barr virus lymphoma with survival: A case report

This is the case report of a 4-year-old white boy who was diagnosed as having acute lymphoblastic leukemia (ALL) in November 1985. While in remission and on maintenance chemotherapy, he developed a primary Epstein-Barr virus (EBV) respiratory infection in October 1986. On October 27, 1986 a plain abdominal radiograph taken for abdominal distention showed free air. At celiotomy, multiple nodules were noted to stud the small bowel. Central necrosis of these nodules with perforations were present in the distal small bowel. Resections and end-to-end anastomoses were performed. Three days later the patient again had a similar acute abdominal episode. At reexploration, similar lesions in the liver, kidney, duodenum, proximal jejunum, and colon were found. Liver biopsy as well as intestinal resections and end-to-end anastomoses were performed, along with a loop ileostomy. Polymorphic B-cell lymphoma positive for EBV was found in the specimens. After cessation of chemotherapy and institution of abdominal radiotherapy, the hepatic and renal lesions were seen to resolve on computed tomography scan. The patient's course was complicated by the development of cervical and mediastinal abscesses that were drained, and E coli sepsis accompanied by chronic diarrhea requiring intravenous hyperalimentation. By January 1988, he appeared to be recovering. His ileostomy was closed in March 1988. Despite cessation of chemotherapy since October 1986, the patients is now well and in complete remission.

Ventricular energetics

Ventricular energetics

Postoperative intra-abdominal and pelvic sepsis complicating ileal pouch-anal anastomosis.

In a series of 500 patients who underwent ileal pouch-anal anastomosis for ulcerative colitis or polyposis coli, significant intra-abdominal or pelvic sepsis developed in 30 (6%). Among the patients who did not require laparotomy because they responded to treatment with antibiotics or local drainage (surgical or radiologically guided) or both, no pouches were excised and the ileostomy closure rate (92%) was similar to that for the patients who did not have sepsis. The 17 patients whose sepsis did require laparotomy had a high rate of pouch excision (41%) (p less than 0.0001) and a low rate of ileostomy closure (29%) (p less than 0.0001). Factors identified as possibly associated with severe sepsis included female gender and ulcerative colitis complicated by toxicity or malignancy.

HEREDITARY COPROPORPHYRIA

Abstract A family with hereditary coproporphyria from central Jutland, Denmark, is described. In spite of excretion of considerable amounts of coproporphyrin III with the feces, but no protoporphyrin, and occasionally increased urinary porphyrin as well as porphyrin precursors (PBG and/or ALA) in the urine, all the affected members except one were completely free from symptoms of porphyria during the four years the family was under observation. The only member of the family exhibiting symptoms had a mild attack of acute intermittent porphyria type, presumably provoked by barbiturates, accompanied by pyelonephritis and coli sepsis. She constantly excreted high amounts of coproporphyrin III in her feces and, periodically at least, increased coproporphyrin and slightly increased uroporphyrin with the urine. In most of her siblings the excretion was intermittent and in all of them it was considerably lower than in the patient, although highly elevated. Among the next generation the excretion was much lower. The observations support the concept of dominant inheritance.

Characterization of a myocardial depressant factor present in hemorrhagic shock.

Characterization of a myocardial depressant factor present in hemorrhagic shock.