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This study examined the effects of 1 degrees C hypo- or hyperthermia on in vivo liver ischemia and reperfusion (I/R) injury in 15 fasted male Wistar rats. Rats were ventilated, and rectal temperature was maintained at 36, 37 (normothermic), or 38 degrees C. In all rats, 70% liver ischemia was induced by clamping the afferent vessels to the median and left lateral lobes for 60 min, and reperfusion was allowed for 90 min. Changes in plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alpha-glutathione S-transferase (alpha-GST) levels were measured, hemodynamics and bile secretion were monitored, and arterial blood-gas analysis was performed. All ventilated rats showed a normal pH, arterial PCO(2), and arterial PO(2). AST, ALT, and alpha-GST levels were significantly higher in the 38 degrees C group when compared with the 36 and 37 degrees C groups after ischemia. No differences in bile secretion were found between all groups. Histopathological alterations were in agreement with AST, ALT, and alpha-GST levels in plasma. We conclude that a decrease of only 1 degrees C in body temperature significantly attenuates liver I/R injury, whereas an increase of 1 degrees C significantly increases liver I/R injury.

Background/aim: Both maintenance of adequate perfusion and regeneration of the remnant liver are important in the recovery of liver function after partial hepatectomy. In previous experiments, we have shown that profound hypotension and liver injury can be attenuated by neutralizing endotoxins. The relative contribution of endotoxemia to changes in liver blood flow and blood flow to other major organs after partial hepatectomy is not known. The aim of this study was to examine the effect of endotoxin neutralization on individual organ blood flows including hepatic artery and splanchnic blood flow after experimental partial hepatectomy and its relation to liver cell proliferation., Methods: Male Wistar rats underwent either two-thirds partial hepatectomy or sham operation. Treatment consisted of continuous infusion of recombinant N-terminal bactericidal/permeability-increasing protein (rBPI23) or control protein. At 4 h after surgery, organ blood flows were measured using the radiolabeled microsphere technique, and at 24 h, proliferation index in liver tissue was calculated., Results: After partial hepatectomy, blood flows to virtually all organs were significantly lower as compared to values obtained in sham-operated rats. rBPI23 greatly improved hepatic artery flow (p<0.001) but not portal venous flow. These effects of rBPI23 on liver flow preceded an equally enhanced liver cell proliferation (p<0.01). Endotoxin neutralization led to significantly higher flows to some but not all splanchnic organs. Lung perfusion was significantly improved by rBPI23., Conclusions: Neutralization of endogenous endotoxins improves liver blood flow after partial hepatectomy and also periportal and pericentral liver cell proliferation. This proliferation effect may result from an increased hepatic artery flow. Lung, colon, spleen and pancreas flow but not kidney flow was greatly enhanced by rBPI23.

The increasing technological complexity of surgery demands objective evaluation of surgical techniques. In particular, alternatives for laparoscopic ligation, such as monopolar coagulation and the relatively new bipolar scissors combining dissection with coagulation, should be analyzed and compared. This study tests the efficacy of quantitative time-motion analysis in evaluating and comparing the functionality and efficiency of dissection and ligation techniques in a clinical setting. Standard dissection with ligation of vessels, bipolar scissors, and monopolar coagulation were consecutively applied to dissect 4 of the small bowel mesentery of pigs, in random order. All actions performed were recorded and analyzed, using a standard action list. The efficiency of each technique was expressed in mean dissection time and number of actions, and the safety in occurrence of complications and severity of microscopic damage. Time-motion analysis evaluated the efficiency objectively and reproducibly (ICC 0.98). Bipolar scissors were significantly more efficient (time 7 +/- 2 min, actions 129 +/- 33) than the standard technique (28 +/- 6, 771 +/- 185) and monopolar coagulation (14 +/- 5, 368 +/- 32) (p < 0.01). Furthermore, bipolar coagulation needed significantly less recoagulation of an oozing vessel (0.5% of the total dissected vessels) than did monopolar coagulation (10.4%), and the damaged zone was significantly smaller (p < 0.05). Significantly less time was spent waiting or exchanging instruments with bipolar scissors than with the standard technique (p < 0.05). This time-motion analysis objectively compared the efficiency and functionality of three surgical dissection techniques during clinical use. Bipolar scissors were more efficient than were both other techniques, and they coagulated vessels more safely than did monopolar coagulation.

Animal models of liver ischaemia and reperfusion are frequently used to study the consequences on liver cells of transient oxygen deprivation. In 3 different rat models we studied ischaemia/reperfusion effects on liver cell membrane integrity, cytoplasmic enzyme proteins and enzyme activities by in situ histochemical techniques. In vivo ischaemia, as well as no-flow hypoxia, or N2-induced hypoxia in isolated perfused livers, reduced the activity of 5'-nucleotidase, a sensitive marker for plasma membrane damage in hepatocytes. As little as 2 minutes of reoxygenation in each model resulted in leakage of soluble enzymes from parenchymal and non-parenchymal liver cells, as shown by decreased protein level and activity of cytoplasmic enzymes. Whereas a multifocal decrease was observed after in vivo reperfusion, a decrease was found in all periportal and midzonal cells after blood-free reoxygenation. As judged by alkaline phosphatase activity and immunohistochemistry, an influx of inflammatory cells was not found in the in vivo model. Our findings indicate that reoxygenation itself, rather than restoration of flow, accounts for the loss of soluble enzymes from liver cells after a period of hypoxia. In situ detection of enzyme protein and activity proved useful for the examination of very early ischaemia/reperfusion effects on rat liver cells.

This study was performed to clarify the mechanisms underlying post-resection changes in liver cell proliferation and metabolism. To assess the role of gut-derived endotoxaemia and endogenous cytokines in these changes, the effects of peri-operative treatment with either the lipopolysaccharide-neutralizing bactericidal/permeability-increasing protein or interleukin-1 receptor antagonist were investigated at 24 h after two-thirds hepatectomy in rats. Peri-operative treatment with either agent caused enhanced expression of proliferating cell nuclear antigen (PCNA) and reduced lipid accumulation. Activity of the hexose monophosphate shunt was significantly decreased after partial hepatectomy and restored by interleukin-1 receptor antagonist only. After partial hepatectomy, bile canalicular alkaline phosphatase activity was significantly increased in pericentral zones and redistributed to both bile canalicular and sinusoidal membranes of hepatocytes. These effects were not significantly influenced by either treatment. It is concluded that endotoxin restricts liver cell proliferation and leads to lipid accumulation following partial hepatectomy, and that interleukin-1 is a principal mediator in these processes. Furthermore, interleukin-1 mediates a repression of the pentose phosphate pathway. These changes may be of significance with respect to liver function, at least in the early phase after partial hepatectomy.

Impairment of various functions of the liver and concomitantly increased levels of parameters of liver damage, a clinical entity termed liver failure, is commonly seen after partial hepatectomy. We investigated in a rat model whether damage of the remnant liver was due to local inflammatory responses, and related to endotoxin or interleukin-1 (IL-1). To address this question, the effects of partial hepatectomy on infiltration of immunocompetent cells and expression of major histocompatibility complex (MHC) class II antigen of macrophages in the remnant liver was studied using immunohistochemical techniques. Specific intervention with recombinant N-terminal bactericidal/permeability-increasing protein (rBPI23) to neutralize endotoxin and with IL-1 receptor antagonist (IL-1ra) to block IL-1 activity was used to examine the respective roles of endotoxin and IL-1. After partial hepatectomy, we found an influx of neutrophils, an increased expression of MHC class II antigens, and morphologic changes of Kupffer cells consistent with activation. These inflammatory events coincided with increased serum levels of markers of liver damage (aspartate aminotransferase, alanine aminotransferase, ammonia). Both neutralization of endotoxin and blocking of IL-1 activity reduced hepatic inflammation and reduced serum levels of aminotransferases and ammonia. In addition, liver cell proliferation as assessed by staining for proliferating cell nuclear antigen (PCNA) expression was significantly enhanced when either endotoxin or IL-1 effects were blocked. Thus, our results suggest that local hepatic inflammatory responses inhibit liver cell proliferation and promote liver failure, presumably by affecting the functional capacity of the remnant liver.

As the early rat decidua is believed to fulfil functions other than the late or basal decidua, the question as to whether this difference is reflected in decidual cell metabolism was investigated. Using cryosections of pregnant rat uteri of the 10th, 15th and 21st gestational day, activities of oxyradical-forming enzymes and hydrolases were analysed histochemically. The enzyme activities of decidual stromal cells and fibroblasts of the metrial gland exhibited three main fluctuations. One group of enzyme activities did not change during gestation, a second group decreased or disappeared, and a third group increased or was expressed in the late decidua only. Enzymes of the purine and polyamine pathway, including oxyradical-forming oxidases, were absent from early mesometrial decidual cells, but were highly active in the late regressing decidua and metrial gland. Some acid hydrolases and neutral proteases became active in the mature decidua. The possibility that purine-degrading and oxyradical-forming enzymes support decidual as well as metrial gland regression, and thus placental separation, by direct tissue damage and/or by indirect rupture of lysosomal membranes, inducing the release of acid hydrolases, is considered.

In order to understand more about participation of the basal placental zones in processes of regression and degradation as well as separation on the cellular level, the cell metabolism of the rat decidua and metrial gland was investigated enzyme histochemically in cryosections for activities of oxyradical-forming enzymes and hydrolyzing enzymes. Additionally, plastic sections were studied to facilitate the recognition of cell types. Decidual stromal cells and fibroblasts formed the vast majority amongst many cell types in the decidua and metrial gland. High activities of enzymes involved in purine degradation and oxyradical generation were demonstrated in decidual stromal cells and fibroblasts. Microsomal alanyl aminopeptidase and various acid hydrolases were shown to be extremely active in decidual stromal cells. The abundance of these enzyme activities in the decidua and metrial gland in contrast to other placental areas suggests, that these enzymes may have specialized functions in connection with regression and degradation processes finally contributing to placental separation.

A histochemical analysis of reaction rates of a series of enzymes was performed in electromotor neurons of the weakly electric fish Apteronotus leptorhynchus. These neurons were selected because of their functional homogeneity. The high metabolic activity of these cells as well as their large size facilitate cytophotometric analysis in cryostat sections. Sections were incubated for the activity of hexokinase, glucose-6-phosphate dehydrogenase, succinate dehydrogenase, NADPH dehydrogenase, NADPH ferrihaemoprotein reductase and beta-hydroxybutyrate dehydrogenase. All media contained polyvinyl alcohol as tissue stabilizer and Nitro BT as final electron acceptor. Measurements were performed with a Vickers M85a cytophotometer. Linear relationships between the specific formation of formazan (test minus control reaction) and incubation time were obtained for all enzymes although some reactions showed an initial lag phase or an intercept with the ordinate. The relatively high activities of hexokinase, succinate dehydrogenase and the extremely low activity of hydroxybutyrate dehydrogenase indicate that energy is mainly supplied by glycolysis. Glucose-6-phosphate dehydrogenase showed a high activity whereas NADPH reductase and dehydrogenase activity were low in electromotor neurons, indicating that the NADPH generated is largely used for biosynthesis. Despite their synchronous firing pattern activity, electromotor neurons showed a considerable heterogeneity with respect to their metabolic activity.