Liposomal ATP protects the liver from injury during shock.

Liposomes are useful drug carriers. In this study, adenosine triphosphate (ATP) was entrapped in liposomes (Lip-ATP). Anesthetized rats were given Lip-ATP (5 mg/kg as ATP), free ATP (5 mg/kg) or saline (control group) during stabilization. Then, the rats were exposed to 30 min of hypovolemic shock and 30 min of reperfusion. Administration of Lip-ATP significantly improved hepatic blood flow during shock (13.2 +/- 1.7 ml/min/100 g tissue in the Lip-ATP group vs. 9.4 +/- 2.2, in the control group, and 8.9 +/- 2.9 in the free ATP group) and during reperfusion (20.9 +/- 2.3, 16.3 +/- 2.2, and 16.2 +/- 1.8 ml/min/100 g tissue, respectively). The serum levels of hepatic enzymes (ALT, AST and LDH) were significantly lower in the Lip-ATP group after reperfusion when compared with the control and free ATP groups. Administration of Lip-ATP also produced the best recovery of hepatic ATP level. These findings indicate that Lip-ATP increased hepatic blood flow during shock and reperfusion, presumably by improving the energy charge and metabolism of the hepatocytes. Thus, Lip-ATP appears to be a useful agent for liver injury induced by hypovolemic shock.

Cytokines affect pseudomonas binding to tracheal cells via a neutrophil-mediated process.

Critical illness is often associated with gram-negative bacterial colonization of the airways, increasing the risk of nosocomial pneumonia. Cytokines, released in response to endotoxin, might contribute to this phenomenon by causing changes in epithelial cell binding of bacteria. To investigate this possibility, human monocytes and hamster pulmonary macrophages were cultured without or with Escherichia coli endotoxin (10 micrograms/ml) for 4 and 24 h. Hamster and human tracheal epithelial cells were treated with supernates from monocyte cultures for 24 h, and subsequent binding of 14C-labeled Pseudomonas aeruginosa to the epithelial cells was measured (percent adherence). In separate experiments, recombinant human (rh) tumor necrosis factor-alpha (TNF-alpha) (25 to 100 ng/ml) and interleukin-1 beta (IL-1 beta) (2,000 to 8,000 pg/ml) were added to hamster monolayers. Neither monocyte supernates nor purified cytokines were toxic to the epithelial cells for up to 48 h. There was no significant change in P. aeruginosa adherence to either hamster or human tracheal epithelial cells after 24 h of exposure to culture supernates from either endotoxin-stimulated human monocytes or hamster macrophages. Similarly, purified rhTNF and rhIL-1 exposure did not increase bacterial adherence. However, when polymorphonuclear leukocytes were coincubated with the monocyte supernates and epithelial cells, P. aeruginosa adherence was significantly increased. Moreover, this effect was enhanced by an epithelial cell-derived substance. Thus, while inflammatory cytokines may participate in enhancing bacterial colonization of the lung in vivo, they do not do so by a direct action on tracheal epithelial cells but can act via a neutrophil-dependent mechanism.

Effect of protease inhibitor on ischemia/reperfusion injury of the rat liver.

The purposes of this study were to clarify the role of neutrophilic proteases in the pathogenesis of hepatic ischemia/reperfusion injury and to determine whether urinary trypsin inhibitor (UTI) pretreatment attenuated liver ischemia/reperfusion injury in rats. Livers from male Sprague-Dawley rats were subjected to 90 min of no-flow warm ischemia followed by 120 min of reperfusion. Rats were divided into a UTI group and a control group. In the control group, 120-min reperfusion of the liver produced a significant increase in myeloperoxidase activity, a significant decrease in ATP and energy charge, and a marked increase in the serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase levels. In the UTI group, the myeloperoxidase activity was significantly attenuated (P < 0.01), ATP and energy charge were significantly improved (P < 0.01 and P < 0.05, respectively), and the elevation in serum aspartate aminotransferase, alanine aminotransferase, and lactic dehydrogenase was also markedly suppressed (P < 0.05, P < 0.01, and P < 0.05, respectively) compared with the control group. Sections through the livers of control rats showed severe hepatocyte necrosis with neutrophil infiltration. In the UTI group, there was slight congestion and hepatocyte necrosis. The survival rate after 90-min liver ischemia was significantly improved compared with that in the control group (P < 0.05). The results of this study suggest that pretreatment with UTI significantly attenuates liver reperfusion injury, perhaps by inhibiting neutrophil proteases.

Effect of liposomal interleukin-2 on ascites-forming rat hepatoma.

Interleukin-2 was entrapped in liposomes (Lip-IL-2) and injected into rats. The intraperitoneal injection of Lip-IL-2 into rats bearing an ascites-forming rat hepatoma (AH-66) significantly increased the survival time when compared with rats administered free IL-2 or saline-containing liposomes. The number of peritoneal exudate cells (PEC) increased markedly after intraperitoneal injection of Lip-IL-2 and consisted mainly of macrophages. The level of tumor necrosis factor alpha (TNF-alpha) and the intensity of free radicals increased in the ascites at 48 hrs after Lip-IL-2 administration, whereas TNF-alpha was not detected and the intensity of free radicals did not increase after free IL-2 administration. Our findings suggested that entrapment of IL-2 into liposomes enhanced its potential for cancer therapy, presumably by activating macrophages to produce TNF-alpha and free radicals.

[The comparison of postoperative multiple organ failure with arterial disease to that with gastrointestinal cancer].

The clinical features of 22 postoperative multiple organ failure (MOF) patients, comprised of 8 with arterial disease (A-MOF) and 14 with gastrointestinal cancer (G-MOF), were investigated. Differences in the operative time, blood loss, and mortality were not significant. The initial organ impaired was the lungs in 78.6% of G-MOF patients and the heart or kidneys in all A-MOF patients. Infection developed in over 80% of both groups. In many A-MOF patients, the pneumonia or septicemia developed secondary to organ failure, while intraabdominal infection triggered respiratory failure in many G-MOF patients. Our organisms in infected specimens and their antibiotic sensitivities was valuable for the early administration of effective antibiotics. Upper gastrointestinal tract bleeding was important in the prognosis of both groups and occurred more frequently in A-MOF than in G-MOF patients. Consumption coagulopathy in A-MOF patients and DIC induced by infection in G-MOF patients mainly caused such bleeding. Preoperative administration of heparin was effective in improving coagulopathy. Furthermore, measurement of intramural pH with tonometer in the stomach and gastric irrigation with oxygenated perfluorochemicals were effective in the prediction and prevention of gastrointestinal bleeding.

Experimental studies on the prediction and prevention of stress ulcers using tonometry, reflectance spectrophotometry and oxygenated perfluorochemicals.

The present study investigates whether oxygenated perfluorochemicals protect the gastric mucosa against hemorrhage-induced stress ulceration. The influence of oxygenated perfluorochemicals on both macroscopic and microscopic lesion formation, gastric intramural pH, index of oxygen saturation and index of hemoglobin saturation of the gastric mucosa was studied. To assess the severity of gastric mucosal ischemia, intramural pH was directly measured using a pH sensitive microelectrode and indirectly by utilizing hollow viscus tonometry, and the indices of oxygen saturation and hemoglobin saturation were measured by reflectance spectrophotometry. Oxygenated perfluorochemicals (30 ml/kg/h) significantly protected the gastric mucosa against both gross (lesion index 0.85 +/- 0.2 vs 2.23 +/- 0.31) and microscopic (lesion index 0.52 +/- 0.02 vs 2.04 +/- 0.03) injuries. This protection was associated with a significantly decreased acidification of the mucosa during shock (intramural pH 7.24 +/- 0.02 vs 6.97 +/- 0.02) and significantly increased oxygen saturation of the gastric mucosa (30 +/- 6 vs 5 +/- 2). These data indicate that topical oxygenated perfluorochemicals protect the gastric mucosa against mucosal damage provoked by hemorrhagic shock, and this protection seems to be mediated by an increased oxygen saturation of the gastric mucosa. Tonometry and reflectance spectrophotometry thus are able to predict the critical level of gastric mucosal ischemia.

Free radical injury in skeletal muscle ischemia and reperfusion.

This study was made in a canine isolated gracilis muscle model to measure directly the free radicals, to predict the severity of ischemia and reperfusion injury of the skeletal muscle by measuring its surface pH (mspH), and to determine the effect of Coenzyme Q10 (CoQ10) in reducing the extent of muscle injury. Animals were divided into three groups: group A (control, n = 10), group B (untreated, n = 10), and group C (CoQ10 treated, n = 10). In both groups B and C, 5 hr ischemia followed by 40 min of reperfusion was made. Free radicals were measured directly by electron spin resonance spectrometer (ESR) and mspH was measured using a pH microprobe. Serum creatine phosphokinase (CPK) was estimated before ischemia, 5 and 30 min after reperfusion. The extent of muscle injury was evaluated morphologically by Evan's blue dye exclusion test. ESR intensity in group B was 0.55 +/- 0.19 and decreased to 0.30 +/- 0.04 in group C (P less than 0.01). Rate of recovery of mspH was higher in group C (7.16 +/- 0.06) compared to group B (6.88 +/- 0.11, P less than 0.01) and CPK in group C was less (847 +/- 381 IU/liter) than in group B (1356 +/- 519 IU/liter, P less than 0.05) after 30 min of reperfusion. In group C the morphological muscle injury was less (37.8 +/- 5%) compared to group B (56.7 +/- 3.6%, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)