Correlation of rheoencephalogram and intracranial pressure: results of a rat study.

Measuring brain electrical impedance (rheoencephalography-REG) is a potential technique for noninvasive, continuous neuro-monitoring. Typically, intracranial pressure (ICP), an invasive monitoring modality, is used in brain monitoring. Our hypothesis was that both modalities would reflect cerebrovascular reactivity. In the present study we compared results of REG to results of ICP measurement. Rats were used under anesthesia ([Formula: see text]; 36 control and 59 vinpocetine infusions). REG was measured by two bipolar REG amplifiers; time constants (Tc) were 3 and 0.3 s. The vinpocetine injection caused a transient decrease in systemic arterial pressure (SAP) and a simultaneous increase in ICP and REG pulse amplitude. SAP decrease was 25% ± 14%; ICP was 28% ± 16%; REG pulse amplitude increase was 209% ± 17% (Tc 3) and 107% ± 68% (Tc 0.3). ICP increase correlated with REG pulse amplitude increase. Area under the receiver operating characteristic curve was 0.9481 for ICP-REG time constants 3 and 0.9335 for ICP-REG time constants 0.3; both with [Formula: see text]. The fact that both REG and ICP reflect cerebrovascular reactivity indicates the usefulness of REG as a potential technique for noninvasive, continuous neuro-monitoring. The Tc of REG amplifier requires optimization for continuous monitoring of pressure reactivity index.

Early ascorbic acid depletion is related to the severity of acute pancreatitis.

BACKGROUND: Ascorbic acid (AA) is an important endogenous antioxidant in plasma and has been shown to be decreased at the time of hospital admission in patients with acute pancreatitis. The aim of this study was to determine whether plasma AA concentration continues to decrease after admission and whether the extent of decrease is related to the severity of pancreatitis. METHODS: Consecutive patients with mild (n = 62) and severe (n = 23) acute pancreatitis had plasma AA concentration measured on the day of recruitment and on days 2 and 5 by high-performance liquid chromatography. RESULTS: The plasma AA concentration in patients with acute pancreatitis was significantly less than that in normal volunteers on days 0, 2 and 5 (P < 0.0001) and this was more marked in those with severe disease. There was a decrease in plasma AA concentration from day 0 to day 2 in patients with mild (P < 0.0001) and severe (P = 0.0005) pancreatitis, and from day 2 to day 5 in patients with severe pancreatitis (P = 0.023). CONCLUSION: Endogenous plasma AA continues to decrease over the first 5 days in hospital and the extent is related to the severity of acute pancreatitis. Presented to a meeting of the Australasian Surgical Research Society, Auckland, New Zealand, August 1995 and published in abstract form as Aust N Z J Surg 1996; 66: 243

Plasma von Willebrand factor and intestinal ischaemia-reperfusion injury in rats.

The purpose of this study was to determine whether plasma von Willebrand factor concentrations are correlated with the degree of intestinal ischaemia-reperfusion injury. Forty-six anaesthetised adult Wistar rats were divided into five groups. The sham-operated group (S, n=10) had laparotomy and isolation of the superior mesenteric artery without clamping. Three ischaemia-reperfusion groups (n=10 in each) had clamping of the superior mesenteric artery for 15, 30, and 45 minutes, respectively, and reperfusion for 15 minutes. A control group (C, n=6) had direct puncture of the heart to sample blood. Mean arterial pressure was measured continuously. Blood was collected at the end of the study to measure von Willebrand factor. The small bowel injury was graded histologically. There was a significant systemic hypotension after declamping in all ischaemia-reperfusion groups, which had a high negative correlation with the histological score (R=-0.46, F=10.1, p<0.003, simple linear regression). Plasma von Willebrand factor was significantly elevated in the three ischaemia-reperfusion groups compared with the control group but not significantly different from the sham-operated group (mean von Willebrand factor concentration (SEM): 156 (29), 283 (29), 295 (25), 381 (44), and 366 (40)% in C, S, ischaemia-reperfusion 15, ischaemia-reperfusion 30, and ischaemia-reperfusion 45 groups, respectively). The concentration of von Willebrand factor was not correlated to the histological score (R=0.22, F=1.83, p<0.2) or the degree of hypotension after the removal of the clamp (R=-0.22, F=1.8, p<0.2, simple linear regression). This study shows that von Willebrand factor concentration does not correlate with the degree of intestinal ischaemia-reperfusion injury. It is unlikely that von Willebrand factor can be used as a predictor of disease severity.

Small bowel ischaemia-reperfusion increases plasma concentrations of oxidised proteins in rats.

OBJECTIVES: To find out whether plasma concentrations of protein carbonyl (a specific marker of oxidative damage of proteins) are increased during intestinal ischaemia-reperfusion and whether they are correlated with von Willebrand's factor (vWF, a marker of endothelial injury) or myeloperoxidase (a marker of neutrophil activation). DESIGN: Randomised experimental study. SETTING: University department of surgery, New Zealand. ANIMALS: Thirty anaesthetised adult Wistar rats. INTERVENTIONS: The sham operated group (n = 10) had laparotomy and isolation of the superior mesenteric artery without clamping. The ischaemia-reperfusion group (IR, n = 10) had the superior mesenteric artery clamped for 1 hour and reperfusion for 15 minutes. The control group (n = 10) had direct puncture of the heart to sample blood. MAIN OUTCOME MEASURES: Plasma concentrations of protein carbonyl, vWF, and myeloperoxidase. RESULTS: Plasma protein carbonyl concentrations were significantly higher in the IR group than in the sham group (p < 0.02, Mann-Whitney test, median (range) 0.187 (0.141-0.242) compared with 0.144 (0.121-0.185) nmol/mg) and in the control group (p < 0.01, Mann-Whitney test, median (range) 0.187 (0.141-0.242) compared with 0.136 (0.108-0.175) nmol/mg). There was a significant correlation between protein carbonyl and vWF concentrations (r = 0.54, F = 10.9, p < 0.003, linear regression) but not with those of myeloperoxidase. CONCLUSION: Intestinal ischaemia-reperfusion caused an increase in the plasma protein carbonyl concentration, which is possibly produced by endothelial cells.

Anti-inflammatory cytokine response and clinical outcome in acute pancreatitis.

OBJECTIVE: To test the hypothesis that elevated interleukin (IL)-10 plasma concentration relative to IL-6 and IL-8 in patients with acute pancreatitis is associated with improved clinical outcome. DESIGN: Case series. SETTING: University hospital surgical and intensive care unit. PATIENTS: Patients with mild (n = 18) and severe (n = 14) acute pancreatitis were recruited within 12 hrs of admission and studied for 5 days. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The plasma concentration of IL-10 was significantly elevated in patients with severe pancreatitis during the 5 days and especially so in those who died compared with survivors on day 5 (p <.03). The ratio of IL-10/IL-6 was decreased in patients with severe pancreatitis on day 5 (p < .01). There was a significant decrease in the ratio of IL-10/IL-8, but not of IL-10/IL-6, during the first 5 days (p < .014). CONCLUSIONS: The findings are consistent with the hypothesis that an increase in plasma IL-10 relative to IL-6 or IL-8 is associated with improved clinical outcome.

Intestinal ischaemia-reperfusion increases plasma amylin concentration in rats.

Intestinal ischaemia-reperfusion and hyperamylinaemia are both associated with severe acute pancreatitis. The aim of this study was to examine the relationship between intestinal-ischaemia reperfusion and plasma amylin in an experimental model. Wistar rats (n = 24, 400-450 g) were divided into three groups: (1) a sham (S)-operated group (n = 7) that underwent laparotomy and isolation (without clamping) of the superior mesenteric artery, (2) an ischaemia-reperfusion (IR) group (n = 7) that had clamping of the superior mesenteric artery for 60 min followed by 15 min reperfusion, and (3) a control (C) group (n = 10) that underwent no surgery. Amylin was significantly elevated in the IR group (median 39 pM, range 30-44) compared with the S group (19 pM, range 15-45; Mann-Whitney U, p < 0.05) and the C group (24 pM, range 15-55; p < 0. 01). Insulin was significantly elevated in the IR group (2,060 pM, range 1,000-4,650) compared with the S group (558 pM, range 424-2, 020; p < 0.01). There was a significant positive correlation between amylin and insulin (R = 0.82, F = 46.6, p < 0.0001), but not between amylin and glucose or insulin and glucose. Intestinal histology was consistent with an ischaemia-reperfusion injury, whereas pancreatic histology was normal. The unique finding that plasma amylin concentration is increased with intestinal ischaemia-reperfusion injury warrants further investigation.

Manganese superoxide dismutase: a marker of ischemia-reperfusion injury in acute pancreatitis?

Recent evidence has suggested that ischemia-reperfusion injury is fundamental to the pathogenesis of acute pancreatitis. This study was designed to determine whether acute pancreatitis is associated with elevated serum manganese superoxide dismutase (MnSOD), a key antioxidant enzyme, considered a marker of ischemia-reperfusion injury in myocardial infarction. Thirty-four patients with acute pancreatitis had measurements of MnSOD on days 0, 2, and 5 after recruitment. The patients were recruited within 12 h of admission to hospital and had measurements of MnSOD on days 0, 2, and 5. Patients with severe acute pancreatitis had significantly elevated serum MnSOD concentrations on days 2 and 5 compared with patients with mild acute pancreatitis, but not on the day of recruitment. Elevated serum MnSOD correlated with peripheral plasma markers of lipid peroxidation (malondialdehyde) and neutrophil activation (myeloperoxidase) and was associated with decreased plasma ascorbic acid concentrations. The serial measurement of serum MnSOD may prove useful as a marker of the effectiveness of treatment designed to limit ischemia-reperfusion injury in patients with severe acute pancreatitis.

Activity of antioxidant defense enzymes and glutathione content in some tissues of the Belgrade (b/b) laboratory rat.

The activity of antioxidant defense (AD) enzymes--superoxide dismutase (SOD, EC 1.15.1.1.), catalase (CAT, EC 1.11.1.6.), glutathione peroxidase (GSH-Px, EC 1.11.1.9.), glutathione-S-transferase (GST, EC 2.5.1.18), glutathione reductase (GR, EC 1.6.4.2) and glutathione (GSH) content of the anemic Belgrade (b/b) laboratory rats--were measured and analyzed in liver, spleen, lung, heart, brain and testes in comparison with nonanemic controls. The activities of hepatic Mn SOD, CAT, GSH-Px and GST (P < 0.02, P < 0.01 and P < 0.005) were decreased in anemic, comparing with nonanemic animals, whereas the spleen CuZn SOD, Mn SOD, CAT and GSH-Px (P < 0.005, P < 0.02, P < 0.005 and P < 0.01) activities were increased. In the lung of anemic rats, Mn SOD, GSH-Px and GR (P < 0.005, P < 0.01, P < 0.05) activities were higher, whereas GST (P < 0.01) activity was lower in relation to nonanemic ones. In anemic rats, heart Mn SOD (P < 0.05) activity was increased, brain GSH-Px (P < 0.005) activity was lower, whereas GR (P < 0.02) activity was higher compared with nonanemic controls. CuZn SOD (P < 0.05) activity in the testes was elevated and GSH-Px (P < 0.05) reduced in anemic animals. GSH content was decreased in the liver (P < 0.01), lung and brain (P < 0.005) and increased in the spleen (P < 0.02) of anemic rats in relation to the controls. Our data suggest phenotype specific differences in the AD system of the Belgrade (b/b) rat tissues in comparison with nonanemic controls.

Gastric intramucosal pH predicts death in severe acute pancreatitis.

BACKGROUND: This study tested the hypothesis that gastric intramucosal pH (pHi) can predict death in severe acute pancreatitis. METHODS: Seventeen consecutive patients with predicted severe acute pancreatitis were studied prospectively. Four died from complications related to pancreatitis. Gastric pHi was measured by nasogastric tonometry at least every 12 h for the first 48 h after admission and then on a daily basis during the first week. RESULTS: The lowest pHi recorded during the first 48 h was significantly less in those admitted to the intensive care unit than that in those who remained on the surgical ward (P = 0.0015) and in nonsurvivors compared with the survivors (P = 0.009). A receiver-operator characteristic curve defined a pHi of 7.25 as the optimal cut-off point to predict death (sensitivity 100 per cent, specificity 77 per cent, overall predictive value 82 per cent). CONCLUSION: These results suggest that splanchnic ischaemia may be an important determinant of outcome in patients with severe acute pancreatitis.

[The effect of gammaphos on the course and outcome of surgical treatment in combined radiation injuries in pigs]. / Uticaj gamafosa na tok i ishod hirurskog lecenja udruzene radijacione povrede u svinja.

The effect of gamaphos (0.6 mmol kg-1 im, 20 min before irradiation) was investigated upon the course and outcome of the surgical management of combined radiation-gunshot injury in pigs. The hypothesis was tested that the infliction of perforating gunshot injury (LD0/30 days) in pigs in the latent phase of the acute radiation injury (LD0/30 days) results in the increase of the lethal outcome. Gamaphos treatment prevented the lethal outcome. Besides, wound reepithelization and granular tissue vascularization in protected pigs was more intensive in comparison with the unprotected ones.

Decreased plasma proteins, increased total plasma-free amino acids, and disturbed amino acid metabolism in the hereditary severe anemia of the Belgrade laboratory (b/b) rat.

The plasma amino acid pattern has been investigated in severely anemic Belgrade laboratory (b/b) rats. Nonanemic heterozygous (b/+) or normal homozygous (+/+) rats of the same age (six weeks) were used as controls. Decreased plasma proteins, increased total free amino acid, and urea concentrations in plasma associated with increased urea and 3-methylhistidine urinary excretion were found, indicating protein and amino acid metabolic alterations in anemic b/b rats. Plasma alanine, glutamine, tyrosine, and phenylalanine concentrations were increased. The significantly reduced molar ratio between valine+leucine+isoleucine and phenylalanine+tyrosine suggested severe disturbance in the hepatic energy-producing system and derangement of hepatic energy status. Partial or complete reversal of the anemia within 3 days by red blood cell transfusion or within 3 weeks by iron treatment resulted in normalization of tyrosine, alanine, glutamine, and total amino acid concentrations in plasma, as well as of molar ratio between valine+leucine+isoleucine and phenylalanine+tyrosine. This indicated a better oxygen supply to the liver and normalization of the hepatic energy status. These findings suggest that the metabolic disturbances in the b/b rat are the consequence of hypoxia due to the severe anemia.

[Pathophysiologic reactions in sheep to blast waves from detonation of aerosol explosives]. / Patofizioloske reakcije kod ovaca na udarni talas nastao detonacijom aerosolnog eksploziva.

In the controlled field experiments 18 sheep were exposed to the detonation of the aerosol explosive generating the blast wave necessary to produce death in 50% of cases. The time of death and characteristic damages on the predilection sites of some organs are interpreted as blast type injuries. General response of the body to blast wave was similar to the one produced by other etiological factors. A special characteristic of the experiment was the frequency and severity of pathologic changes on the internal organs of the chest and abdomen. According to the authors' opinion the severity and type of pathologic changes could be explained by effects of the complex blast wave generated by detonation of the aerosol explosives.

Genetic basis of resistance to trauma in inbred strains of mice.

In this study the resistance to mechanical, thermal, and radiation trauma in four inbred strains of mice (AKR, BALB/c, CBA, and C57Bl/6) was compared with the degree of genetic resemblance, by analyzing the allozyme variabilities of these strains. It was shown that the highest degree of genetic resemblance was among CBA and AKR strains, which correlated with a similar degree of resistance to trauma. On the other hand, BALB/c and C57Bl/6 strains expressed significant differences, both genetically and with respect to the responses to trauma. The hypothesis is introduced that the genetic determination of the resistance to trauma is based on: a) a polygenic control of general physiological homeostasis, with the possibility that b) some specific genes or single loci may contribute more than others to such adaptations of the strains tested.