Dengue virus-elicited tryptase induces endothelial permeability and shock.

Dengue virus (DENV) infection causes a characteristic pathology in humans involving dysregulation of the vascular system. In some patients with dengue hemorrhagic fever (DHF), vascular pathology can become severe, resulting in extensive microvascular permeability and plasma leakage into tissues and organs. Mast cells (MCs), which line blood vessels and regulate vascular function, are able to detect DENV in vivo and promote vascular leakage. Here, we identified that a MC-derived protease, tryptase, is consequential for promoting vascular permeability during DENV infection, through inducing breakdown of endothelial cell tight junctions. Injected tryptase alone was sufficient to induce plasma loss from the circulation and hypovolemic shock in animals. A potent tryptase inhibitor, nafamostat mesylate, blocked DENV-induced vascular leakage in vivo. Importantly, in two independent human dengue cohorts, tryptase levels correlated with the grade of DHF severity. This study defines an immune mechanism by which DENV can induce vascular pathology and shock.

Glycogen synthase kinase 3beta as a target for the therapy of shock and inflammation.

After the discovery that glycogen synthase kinase (GSK) 3beta plays a fundamental role in the regulation of the activity of nuclear factor kappaB, a number of studies have investigated the effects of this protein kinase in the regulation of the inflammatory process. The GSK-3beta inhibition, using genetically modified cells and chemically different pharmacological inhibitors, affects the regulation of various inflammatory mediators in vitro and in vivo. Insulin, an endogenous inhibitor of GSK-3 in the pathway leading to the regulation of glycogen synthase activity, has recently been clinically used in the therapy for septic shock. The beneficial anti-inflammatory effects of insulin in preclinical and clinical studies could possibly be due, at least in part, to the inhibition of GSK-3 and not directly correlated to the regulation of blood glucose. We describe the latest studies describing the effects of GSK-3 inhibition as potential target of the therapy for diseases associated with inflammation, ischemia/reperfusion, and shock.

A journey with Tony Hugli up the inflammatory cascade towards the auto-digestion hypothesis.

My association with Tony Hugli, long-term editor of Immunopharmacology and International Immunopharmacology, came about by a specific and long-standing problem in inflammation research. What is the trigger mechanism of inflammation in physiological shock? This is an important clinical problem due to the high mortality associated with physiological shock. We joined forces in the search of the answer to this question for more than a decade. Our journey eventually led to development of the hypothesis that shock may be associated with pancreatic enzymes, a set of powerful digestive enzymes that are an integral part of human digestion. The digestive enzymes need to be compartmentalized in the lumen of the intestine where they break down a broad spectrum of biological molecules into their building blocks, suitable for molecular transport across the mucosal epithelium into the circulation. The mucosal epithelial barrier is the key element for compartmentalization of the digestive enzymes. But under conditions when the mucosal barrier is compromised, the fully activated digestive enzymes in the lumen of the intestine are transported into the wall of the intestine, starting an auto-digestion process. In the process several classes of mediators are generated that by themselves have inflammatory activity and upon entry into the central circulation generate the hallmarks of inflammation and eventually cause multi-organ failure. Thus, our journey led to a new hypothesis, which is potentially of fundamental importance for death by multi-organ failure. The auto-digestion hypothesis is in line with the century old observation that the intestine plays a special role on shock - indeed it is the organ for digestion. Auto-digestion may be the prize to pay for life-long nutrition.

MK2 phosphorylation of RIPK1 regulates TNF-mediated cell death.

TNF is a master proinflammatory cytokine whose pathogenic role in inflammatory disorders can, in certain conditions, be attributed to RIPK1 kinase-dependent cell death. Survival, however, is the default response of most cells to TNF stimulation, indicating that cell demise is normally actively repressed and that specific checkpoints must be turned off for cell death to proceed. We identified RIPK1 as a direct substrate of MK2 in the TNFR1 signalling pathway. Phosphorylation of RIPK1 by MK2 limits cytosolic activation of RIPK1 and the subsequent assembly of the death complex that drives RIPK1 kinase-dependent apoptosis and necroptosis. In line with these in vitro findings, MK2 inactivation greatly sensitizes mice to the cytotoxic effects of TNF in an acute model of sterile shock caused by RIPK1-dependent cell death. In conclusion, we identified MK2-mediated RIPK1 phosphorylation as an important molecular mechanism limiting the sensitivity of the cells to the cytotoxic effects of TNF.

Autodigestion: Proteolytic Degradation and Multiple Organ Failure in Shock.

There is currently no effective treatment for multiorgan failure following shock other than supportive care. A better understanding of the pathogenesis of these sequelae to shock is required. The intestine plays a central role in multiorgan failure. It was previously suggested that bacteria and their toxins are responsible for the organ failure seen in circulatory shock, but clinical trials in septic patients have not confirmed this hypothesis. Instead, we review here evidence that the digestive enzymes, synthesized in the pancreas and discharged into the small intestine as requirement for normal digestion, may play a role in multiorgan failure. These powerful enzymes are nonspecific, highly concentrated, and fully activated in the lumen of the intestine. During normal digestion they are compartmentalized in the lumen of the intestine by the mucosal epithelial barrier. However, if this barrier becomes permeable, e.g. in an ischemic state, the digestive enzymes escape into the wall of the intestine. They digest tissues in the mucosa and generate small molecular weight cytotoxic fragments such as unbound free fatty acids. Digestive enzymes may also escape into the systemic circulation and activate other degrading proteases. These proteases have the ability to clip the ectodomain of surface receptors and compromise their function, for example cleaving the insulin receptor causing insulin resistance. The combination of digestive enzymes and cytotoxic fragments leaking into the central circulation causes cell and organ dysfunction, and ultimately may lead to complete organ failure and death. We summarize current evidence suggesting that enteral blockade of digestive enzymes inside the lumen of the intestine may serve to reduce acute cell and organ damage and improve survival in experimental shock.

Anti-inflammatory actions of 15-deoxy-delta 12,14-prostaglandin J2 and troglitazone: evidence for heat shock-dependent and -independent inhibition of cytokine-induced inducible nitric oxide synthase expression.

In this study, the anti-inflammatory actions of the peroxisome proliferator-activated receptor (PPAR)-gamma agonists 15-deoxy-delta 12,14-prostaglandin J2 (15-d-delta 12,14-PGJ2) and troglitazone have been examined. Treatment of RAW 264.7 cells and CD-1 mouse peritoneal macrophages with lipopolysaccharide (LPS) + interferon-gamma (IFN-gamma) results in inducible nitric oxide synthase (iNOS), inducible cyclooxygenase (COX-2) and interleukin-1 (IL-1) expression, increased production of nitric oxide, and the release of IL-1. In a concentration-dependent manner, 15-d-delta 12,14-PGJ2 inhibits each of these proinflammatory actions of LPS + IFN-gamma, with half-maximal inhibition at approximately 0.5 microg/ml and complete inhibition at 1-5 microg/ml. The inhibitory actions of 15-d-delta 12,14-PGJ2 on LPS + IFN-gamma-induced inflammatory events are not associated with the inhibition of iNOS enzymatic activity or macrophage cell death, but appear to result from an inhibition of iNOS and IL-1 transcription. In addition, the anti-inflammatory actions of 15-d-delta 12,14-PGJ2 are not limited to peritoneal macrophages, as 15-d-delta 12,14-PGJ2 prevents TNF-alpha + LPS-induced resident islet macrophage expression of IL-1beta and beta-cell expression of iNOS stimulated by the local release of IL-1 in rat islets. 15-d-delta 12,14-PGJ2 appears to be approximately 10-fold more effective at inhibiting resident islet macrophage activation (in response to TNF + LPS) than IL-1-induced nitrite production by beta-cells. Two mechanisms appear to be associated with the antiinflammatory actions of both 15-d-delta 12,14-PGJ2 and troglitazone: 1) the direct inhibition of cytokine- and endotoxin-stimulated iNOS and IL-1 transcription; and 2) the inhibition of IL-1 signaling, an event associated with PPAR-gamma agonist-induced activation of the heat shock response (as assayed by heat shock protein 70 expression). These findings indicate that the PPAR-gamma agonists, troglitazone and the J series of prostaglandins, are potent anti-inflammatory agents that prevent cytokine- and endotoxin-stimulated activation of peripheral and resident tissue macrophages and cytokine-induced iNOS expression by beta-cells by the inhibition of transcriptional activation and induction of the heat shock response.

Heat shock inhibits cytokine-induced nitric oxide synthase expression by rat and human islets.

In this study the effects of heat shock on interleukin-1beta (IL-1)-induced inhibition of islet metabolic function were examined. Treatment of rat islets for 18 h with IL-1 results in a potent inhibition of glucose-stimulated insulin secretion. The inhibitory effects of IL-1 on insulin secretion are completely prevented if islets are pretreated for 60 min at 42 C before cytokine stimulation. Heat shock also prevents IL-1-induced inhibition of insulinoma RINm5F cell mitochondrial aconitase activity. The protective effects of heat shock on islet metabolic function are associated with the inhibition of IL-1-stimulated inducible nitric oxide synthase (iNOS or NOS II) expression. Islets heat shocked for 60 min at 42 C fail to express iNOS (messenger RNA or protein) or produce nitrite in response to IL-1. IL-1-induced iNOS expression by rat islets requires activation of the transcriptional regulator nuclear factor kappaB (NF-kappaB). Heat shock prevents IL-1-induced NF-kappaB nuclear localization by inhibiting inhibitory protein kappaB (IkappaB) degradation in rat islets. Similar to rat islets, heat shock (stimulated by 90 min incubation at 42 C) prevents IL-1 + interferon gamma-induced iNOS expression and NF-kappaB nuclear localization in human islets. IL-1 also stimulates heat-shock protein 70 (hsp 70) expression by rat islets, and hsp 70 expression is dependent on islet production of nitric oxide. Last, evidence is presented that implicates nitric oxide as a stimulus for the expression of proteins that participate in islet recovery from nitric oxide-mediated damage. These studies indicate that heat shock prevents cytokine-induced islet damage by inhibiting iNOS expression, and suggest that nitric oxide is one effector molecule that stimulates the expression of factors involved in beta-cell recovery from nitric oxide-mediated damage.

Effects of tyrphostins and genistein on the circulatory failure and organ dysfunction caused by endotoxin in the rat: a possible role for protein tyrosine kinase.

1 Here we compared the effects of various inhibitors of the activity of protein tyrosine kinase on (i) the expression of the activity of the inducible isoform of nitric oxide (NO) synthase (iNOS) caused by endotoxin (lipopolysaccharide, LPS) in cultured macrophages, (ii) the induction of iNOS and cyclooxygenase 2 (COX-2) protein and activity in rats with endotoxaemia, and (iii) the circulatory failure and organ dysfunction caused by LPS in the anesthetized rat. 2 Activation of murine cultured macrophages with LPS (1 microgram ml-1) resulted, within 24 h, in a significant increase in nitrite (an indicator of the formation of NO) in the cell supernatant. This increase in nitrate was attenuated by the tyrphostins AG126, AG556, AG490 or AG1641 or by genistein in a dose-dependent fashion (IC50: approximately 15 microM). In contrast, tyrphostin A1 (an analogue of tyrphostin AG126) or daidzein (an analogue of genistein) had no effect on the rise in nitrite caused by LPS. 3 Administration of LPS (E. coli, 10 mg kg-1, i.v.) caused hypotension and a reduction of the pressor responses elicited by noradrenaline (NA, 1 microgram kg-1, i.v.). Pretreatment of rats with the tyrphostins AG126, AG490, AG556, AG1641 or A1 attenuated the circulatory failure caused by LPS. Although genistein attenuated the vascular hyporeactivity to NA, it did not affect the hypotension caused by LPS. Daidzein did not affect the circulatory failure caused by LPS. 4 Endotoxaemia for 360 min resulted in rises in the serum levels of (i) urea and creatinine (indicators of renal failure), (ii) alanine aminotransferase (ALT), aspartate aminotransferase (AST), bilirubin and gamma-glutamyl transferase (gamma GT) (indicators of liver injury/dysfunction), lipase (an indicator of pancreatic injury) as well as lactate (an indicator of tissue hypoxia). None of the tyrosine kinase inhibitors tested had a significant effect on the rise i the serum levels of urea, but the tyrphostins AG126, AG556 or A1 significantly attenuated the rises in the serum level of creatinine caused by LPS. In addition, all tyrphostins and genistein attenuated the liver injury/failure, the pancreatic injury, the hypoglycaemia and the lactic acidosis caused by LPS. In contrast, daidzein did not reduce the organ injury/dysfunction or the lactic acidosis caused by LPS. 5 Injection of LPS resulted (within 90 min) in a substantial increase in the serum level of tumor necrosis factor alpha (TNF alpha), which was attenuated by pretreatment of LPS-rats with any of the tyrphostins used. Genistein, but not daidzein, also reduced the rise in the serum levels of TNF alpha caused by LPS. Endotoxaemia for 6 h also resulted in a substantial increase in the expression of iNOS and COX-2 protein and activity in the lung, which was attenuated by pretreatment of LPS-rats with the tyrphostins AG126, AG556 or genistein, but not by daidzein. 6 Thus, tyrphostins (AG126, AG556, AG1641 or A1) and genistein, but not daidzein (inactive analogue of genistein), prevent the (i) circulatory failure, (ii) the multiple organ dysfunction (liver and pancreatic dysfunction/injury lactacidosis, hypoglycaemia), as well as (iii) the induction of iNOS and COX-2 protein and activity in rats with endotoxic shock.

Circulatory failure induced by 35 GHz microwave heating: effects of chronic nitric oxide synthesis inhibition.

Sustained exposure to radiofrequency radiation of millimeter wave (MMW) length produces hyperthermia and subsequent circulatory failure. This study sought to determine whether this phenomenon is altered by chronic pretreatment with the nitric oxide (NO) synthesis inhibitor N omega-nitro-L-arginine methyl ester (L-NAME). Rats drank either 1) water, 2) water + L-NAME, or 3) water + L-NAME + L-arginine (at 20 and 50 times the dose of L-NAME) for 14 days. Ketamine-anesthetized rats were exposed to MMW until mean arterial blood pressure (MAP) fell to 75 mmHg, at which point MMW exposure was discontinued. MAP initially increased during exposure in all groups; the pressor response in L-NAME-treated rats was greater than that in water-drinking rats. Subsequently, MAP fell in all groups. The MMW exposure time required to reach MAP = 75 mmHg was significantly reduced in L-NAME-treated rats, although survival times (post-MMW) of L-NAME-treated and control rats were not statistically different. Coadministration of L-arginine abolished the enhanced pressor response produced by L-NAME, but did not completely reverse the shortened MMW exposure time in L-NAME-treated rats. Thus, chronic NO synthesis inhibition with L-NAME reduces the ability of rats to withstand 35 GHz microwave heating, suggesting that NO does not mediate the hypotension produced by this form of hyperthermia.

Zonal heterogeneity of hepatic injury following shock/resuscitation: relationship of xanthine oxidase activity to localization of neutrophil accumulation and central lobular necrosis.

Post-ischemic hepatic injury is characterized by zonal heterogeneity of injury (central lobular necrosis), sinusoidal neutrophil accumulation, and injury generated by reactive oxygen metabolites. We evaluated the role of the heterogeneous distribution of hepatic xanthine oxidase in the generation of neutrophil accumulation and consequent hepatocellular injury in rats subjected to shock [controlled hemorrhagic hypotension (mean arterial pressure = 37.5 + or - 2.5 mmHg for 120 min)], with or without subsequent resuscitation and hemodynamic stabilization, compared with sham-operated rats. Shock/resuscitation produced striking neutrophil accumulation (assayed by esterase histochemistry) in the pericentral sinusoids, associated with centrolobular necrosis. This paralleled the pericentral distribution of xanthine oxidase (determined by histochemical assay of frozen sections) and its release from the liver into the circulation at resuscitation. Pretreatment with allopurinol inhibited hepatic xanthine oxidase activity, neutrophil accumulation, and pericentral hepatocyte necrosis in shock/resuscitation in rats. These findings suggest that reactive oxygen metabolites generated by heterogeneously distributed xanthine oxidase may contribute to the heterogeneity of hepatocellular injury in "ischemic hepatitis."

Plasma glutathione S-transferase as an early marker of posttraumatic hepatic injury in non-human primates.

We have hypothesized that the measurement of alpha-glutathione S-transferase (alpha-GST) in serum may provide a suitable sensitive marker of shock-induced liver damage. Six male adult baboons were studied. Hemorrhage was induced by blood withdrawal of 60-70% of the total blood volume down to an arterial pressure of 35-40 mmHg. Then the reinfusion was performed with the heparinized shed blood plus the same amount of Ringer's solution over the next 4 h. Before the start of hemorrhage, 2 mL/kg zymosan-activated plasma was infused to simulate trauma-related complement activation. alpha-GST antigen levels were determined using an anti-human alpha-GST immunoassay (Hepkit). Concentrations of alpha-GST at baseline in baboon were found to be 3.1 +/- 1.8 ng/mL; at the end of the shock period a significant increase in alpha-GST serum levels (74.8 +/- 13.8 ng/mL) was found. In contrast, transaminase levels did not significantly change. From the current evidence in posttraumatic non-human primates, which resemble the clinical situation in several aspects, alpha-GST measurements are a suitable marker of early hepatocellular injury.

Liver protein kinases in shock: I. Endotoxin administration inactivates protein kinase a in dog liver.

Effects of endotoxin administration on protein kinase A (cAMP-dependent protein kinase) activity in dog liver were investigated. Hepatic protein kinase A was extracted and partially purified by acid precipitation, ammonium sulfate fraction, and DEAE-cellulose chromatography. Protein kinase A was eluted from DEAE-cellulose column with a linear NaCl gradient. Two peaks of protein kinase A, type I (eluted at low ionic strength) and type II (eluted at high ionic strength), were collected, and their activities were determined based on the rate of incorporation of [gamma-32P]ATP into histone. The results obtained 4 h after endotoxin administration (.5 mg/kg, intravenously) show that type I protein kinase A activity was unaffected, while type II protein kinase A activity was inhibited by 26-57%. Kinetic analysis of the data on type II protein kinase A reveals that the Vmax values for ATP, cAMP, and histone were decreased by 31, 39, and 36%, respectively; while the S.5 (substrate concentration required for half-maximal enzyme activity) values for ATP, cAMP, and histone were unaffected following endotoxin administration. These data indicate that endotoxin administration inhibits hepatic type II protein kinase A activity and the nature of inhibition is by a mechanism not competing with ATP, cAMP, and histone reactive sites. Since protein phosphorylation plays an important role in the regulation of cell metabolism and function, our finding may contribute to the understanding of hepatocellular dysfunction during endotoxin shock.

Hypovolemic shock promotes neutrophil sequestration in lungs by a xanthine oxidase-related mechanism.

Our results suggest that xanthine oxidase (XO) contributes to lung neutrophil sequestration in hypovolemic shock. Catheterized rats subjected to shock by phlebotomy (approximately 30% blood loss) had decreased mean arterial blood pressures (P less than 0.05) and increased (P less than 0.05) lung myeloperoxidase (MPO) activities (indicative of lung neutrophil accumulation) compared with sham-treated normotensive rats. In contrast, rats depleted of lung and plasma XO activity by tungsten diet before phlebotomy had decreased (P less than 0.05) lung MPO activities compared with phlebotomized rats fed regular diets.

Myocardial performance after contusion with concurrent hypovolemia.

Myocardial contusion may present as a benign nonclinical event or a life-threatening emergency. Although cardiac output is recognized to be decreased with major contusion, the contribution of hypovolemic shock to myocardial dysfunction is unclear. This study was designed to evaluate the relationship between myocardial contusion and hypovolemic shock. After Sprague-Dawley rats were anesthetized, contusions were administered at either 80 psi or 120 psi. Half of each group then underwent hypovolemic shock. After 24 hours of recovery, cardiac hemodynamics were studied in each subgroup using the Neely-Langendorff apparatus. Isoenzymes and histology were evaluated as well. The data showed that rats undergoing hypovolemic shock in each subgroup had a significant decrease in cardiac output when compared with their controls. This decrease was more pronounced in the 120-psi group. Cardiac isoenzyme levels were elevated in all groups. Microscopic evaluations showed contusion in the controls and necrosis in the shock groups. Patients whose injuries are compatible with myocardial contusion and hypovolemic shock should be resuscitated quickly and evaluated for myocardial dysfunction secondary to infarction.

Guanine deaminase in serum as an indicator of survival probability in severe shock patients.

To find ways of predicting survival or death in cases of severe shock, arterial blood pH and gases, vital signs, and the half-life of activity in the enzymes guanine deaminase, aspartate aminotransferase (AST) and alanine aminotransferase (ALT), were studied in 24 patients. The mean arterial blood pH (+/- SD) in survivors was 7.325 +/- 0.092 while that in non-survivors was 7.108 +/- 0.251 (p less than 0.05). The mean half-life of guanine deaminase in survivors was 19.8 +/- 3.3 hours, while that in non-survivors was 58.6 +/- 11.8 hours (p less than 0.001). When the screening values were set at 7.190 for the arterial blood pH and 36 hours for the half-life of guanine deaminase activity, the 'validity' (sensitivity plus specificity) for the combination of the two tests was 1.88. The values may be useful for the prognosis of survival in severe shock patients.

The proteinases in shock.

The nomenclature of proteinases and their role in shock are reviewed. The regulation of the kallikrein-kinin system, coagulation and fibrinolysis is described with special emphasis on the role of granulocytes for the proteolysis in shock particularly in the lung. The effect of proteinase inhibitors on such systems is described, together with proteinase inhibitors effects on granulocytes and their possible role in the prevention especially of lung damage after shock.

Pancreatic involvement during the early phase of shock.

BACKGROUND: There is a lack of data concerning pancreatic involvement during shock. AIM: To evaluate possible pancreatic alterations in the early phase of shock. SETTING: Twelve consecutive patients with shock were studied within 2 hours from the onset of illness. Seven patients died during the hospital stay: 3 within 4 hours from admission, 3 within 4-8 hours and 1 within 12 hours. MAIN OUTCOME MEASURES: Amylase, lipase, C-reactive protein, amyloid A, interleukin 6, procalcitonin and vascular cell adhesion molecule-1 serum concentrations were determined on admission and 4, 8, and 12 hours afterward. All patients underwent imaging studies of the pancreas. RESULTS: None of the patients developed clinical signs or morphological alterations compatible with acute pancreatitis. Serum amylase levels were above the upper reference limit in 7 patients (58.3%) and serum lipase levels in 2 patients (16.7%; P=0.062). There were no significant differences found between survivors and non-survivors in the serum concentrations of all the proteins studied. CONCLUSIONS: In patients with shock, amylase seems to be more frequently elevated than lipase. None of the patients showed pancreatic alterations at imaging techniques.

Novel beneficial mechanisms of defibrotide, a prostacyclin enhancing agent in splanchnic artery occlusion and reperfusion in rats.

To further clarify the protective mechanism(s) of defibrotide in splanchnic artery occlusion (SAO) shock, we observed the effect of defibrotide on polymorphonuclear leukocyte (PMN) accumulation in the intestinal tissue, gastric lysosomal hydrolases and endothelial function of the ischemia-reperfused superior mesenteric artery (SMA). Pentobarbital anesthetized rats were subjected to occlusion of both the celiac and superior mesenteric arteries for 90 min followed by 2 h reperfusion. The rats receiving only the vehicle for defibrotide exhibited a marked increase in intestinal myeloperoxidase (MPO) activity and a significant endothelial dysfunction manifested by the loss of endothelium-dependent vasorelaxation. Only 2 of 6 rats (33%) survived 2 h of reperfusion. In contrast, those rats treated with defibrotide exhibited significantly attenuated PMN accumulation in intestinal tissue, enhanced endothelium-dependent vasorelaxation in SMA rings, prolonged survival time and increased survival rate to 6 of 7 (i.e., 86%). However, addition of defibrotide in vitro had no direct effect on LTB4 activated PMN adherence to vascular endothelium. Moreover, defibrotide preserved gastric lysosomal membranes in vitro. These results indicate that the protective effect of intravenous administration of defibrotide on SAO shock may be related to its endothelial preserving effect reducing PMN adherence and protection of endothelial and lysosomal membrane integrity.

[Myocardial pathomorphology in exotoxic shock]. / Patomorfologiia miokarda pri ékzotoksicheskom shoke.

Morphological, including electron microscopic, examinations of the hearts from 49 patients dying in the stage of shock after acute poisoning revealed general structural alterations in the myocardium typical of shock of any etiology as well as some specific features of the heart involvement related to the kinds of toxicity. The general alterations include damage of microcirculation vessels, rheological blood disorders, interstitial edema, leading to disorders in cardiomyocyte metabolism and development in some of them of dystrophic and necrotic lesions. In acetic acid poisoning, fatty degeneration of cardiomyocytes is more marked; dichlorethane poisoning is characterized by contractural lesions, and that with cardiotoxic substances by diffuse edema of sarcoplasm with "disconnected" organelles.

[Effect of verapamil on the activity of Ca2+-, Mg2+-dependent endonucleases in hypothalamic cell nuclei in long-term hypovolemic shock]. / Vliianie verapamila na aktivnost' Ca2+-, Mg+-zavisimykh éndonukleas v kletochnykh iadrakh gipotalamusa pri dlitel'nom gipovolemicheskom shoke.

Experiments on anesthetized non-inbred 8-17 kg b.w.dogs have demonstrated that cerebral ischemia consequent to 4-hour hypovolemic shock activates Ca(2+)-, Mg(2+)-dependent endonucleases in cell nuclei of the hypothalamus. Intravenous injection of calcium channels blocker verapamil (Orion) in a dose 0.1 mg/kg 30 min before blood loss prevents activation of the above endonucleases and makes it possible to avoid internucleosome fragmentation of genome DNA.