Non-surviving Animals Research Articles

Fentanyl overdose: Temporal effects and prognostic factors in SKH1 mice.

Fentanyl exposure and overdose are growing concerns in public health and occupational safety. This study aimed to establish parameters of fentanyl lethality in SKH1 mice for future overdose research. Lethality was determined using the up-down procedure, with subjects monitored post-administration using pulse oximetry (5 min) and then whole-body plethysmography (40 min). Following the determination of subcutaneous dose-response, [18F]Fluorodeoxyglucose positron emission tomography (18 F-FDG PET) was performed after LD10 fentanyl at 40 min, 6 h, 24 h or 7days post-dose. LD10 and LD50 were observed to be 110 and 135 mg/kg, respectively, and consistent with four-parameter logistic fit values of 111.2 and 134.6mg/kg (r2 =0.9996). Overdose (LD10 or greater) yielded three distinct cardiovascular groups: survival, non-survival with blood oxygen saturation (SpO2) minimum ≥37% and non-survival with SpO2 <37%. Breaths per minute, minute volume and inspiratory quotient were significantly different between surviving and non-surviving animals for up to 40 min post-injection. 18 F-FDG PET revealed decreased glucose uptake in the heart, lungs and brain for up to 24 h. These findings provide critical insights into fentanyl lethality in SKH1 mice, including non-invasive respiratory effects and organ-specific impacts that are invaluable for future translational studies investigating the temporal effects of fentanyl overdose.

Artificial hypobiosis as a method of G-force negative impact reduction

Dynamic gravitational acceleration, known as a G-force, is an extreme factor for some professions. G-force negative impact realizes in central nervous system adequate functioning disturbance, resulting from oxygen starvation of tissues due to hemodynamic disorders. Known methods of G-force protection are aimed at increasing the maximum short-term G-force value, but not its total safe duration. In a number of studies, in order to increase the maximum value of the tolerated overload, we introduced laboratory animals into a state of artificial hypobiosis. The authors noted a decrease in mortality with an increase in the maximum value of the overload force. There were no data on manifestations of disorders of the central nervous system and recovery time, as well as changes in the safe duration of overload.&#x0D; The study aims to assess the change in the safe G-force duration while artificial hypobiosis.&#x0D; Scientists have used Syrian male hamsters weighing 95.5=0.5 g (M=m) in the study. We have divided the animals into groups — experimental and control.&#x0D; To induce artificial hypobiosis, the researchers administered intramuscular injections of a suspension of α-methyldopa to animals of the experimental group. The control group received of 0.9% NaCl. We have carried out dynamic gravitational acceleration modeling using a centrifuge (r=0.62 m). The animals of both groups were conscious, with positive G-forces pointing downward (head-pelvis).&#x0D; Within 10 seconds (s), the centrifuge rotation speed was increased till the chosen G-force value, G: 30 (angular velocity (ω)=21.79 rad/s), 40 (ω=25.16 rad/s) or 70 (ω=33.28 rad/s). G-force exposure set time, s: 20, 50, 80, 110 or 140. After a complete stop for 10 seconds, the general condition of the animals, injuries, hemorrhages, breathing, heart contractions were assessed. We monitored the surviving animals, assessed consciousness, determined coordination disorders in accordance with the following criteria: animal posture, productive movement, unstable gait, circular motion, reclining on the side. The time of restoration of coordination was also determined. The researchers have observed the animals during the following days to assess the daily survival rate. Necropsy was performed on all non-surviving animals.&#x0D; Survival in the control group: 30 G: 80 s — 5/6; 40 G: 20 s — 6/6, 50 s — 6/6, 80 s — 3/6; 70 G: 20 s — 6/6, 50 s — 4/6, 80 s — 0/10. Survival in the experimental group: 70 G: 50 s — 6/6, 80 s — 10/10, 110 s — 10/10, 140 s — 2/6.&#x0D; After acceleration of 70 G 50 s in animals of the experimental group, coordination disorders were weakly expressed, the coordination recovery time was 1.8±0.3 s, in animals of the control group, violations were assessed as significant, the recovery time was 4.5±0.3 s, which is 2.5 times (p&lt;0.01) more.&#x0D; On the following day, tremor persisted in 3 animals of the control group 40 G 80 c. In the remaining animals of all groups, no coordination disorders or peculiarities were detected.&#x0D; We did not find any external injuries in any animal. Also, the scientists did not reveal a violation of the integrity of tissues according to the results of histological examination.&#x0D; The authors have proved a 5.5-fold increase in the time of safe stay of animals in a state of artificial hypobiosis during dynamic overloads. There was a 2.5-fold decrease in the coordination recovery time in animals in a state of artificial hypobiosis.&#x0D; Ethics. Studies involving laboratory animals were conducted in compliance with the necessary regulations (the Helsinki Declaration of 2000 on Humane Treatment of Animals and the "Rules for carrying out work using experimental animals" (Order of the Ministry of Health of the USSR No. 755 of 12.08.1977)). The Ethics Committee of Izmerov Research Institute of Occupational Health approved the protocol of the study.

Early biomarkers predicting outcome in a porcine model of acetaminophen intoxication: A pilot study.

Acetaminophen intoxication has become the leading cause of acute liver failure (ALF) in Europe and the USA. To identify early biomarkers in order to predict the development of ALF in a porcine model of acetaminophen intoxication. Six German Landrace pigs received a single acetaminophen bolus of 1 g/kg body weight via a jejunal catheter. Cytokines and laboratory parameters were analyzed at 8-hour intervals for a total of 40 h. Three of the 6 animals survived the intoxication. The nonsurviving animals had an increase in serum lactate and interleukin (IL)-6, with a simultaneous decrease in prothrombin time (PT) and albumin concentration 8 h after intoxication. In all nonsurviving animals, elevated levels of tumor necrosis factor alpha (TNF-α) at baseline before intoxication and during the course of ALF were observed. The acetaminophen serum concentrations and toxicokinetics did not differ between the nonsurviving and surviving animals. Methemoglobinemia was proportional to the administered doses and acetaminophen blood levels, but methemoglobinemia did not affect survival. Tumor necrosis factor alpha, IL-6, lactate, prothrombin time, and albumin blood concentration were identified as early predictors of outcome after acetaminophen intoxication. An elevated TNF-α level before acetaminophen exposure was the earliest prognostic marker for a lethal outcome. Therefore, it could serve as a very early indicator of prognosis.

Postinjury Treatment to Mitigate the Effects of Aeromedical Evacuation After Traumatic Brain Injury in a Porcine Model

IntroductionEarly aeromedical evacuation after traumatic brain injury (TBI) has been associated with worse neurologic outcomes in murine studies and military populations. The goal of this study was to determine if commonly utilized medications, including allopurinol, propranolol, or tranexamic acid (TXA), could mitigate the secondary traumatic brain injury experienced during the hypobaric and hypoxic environment of aeromedical evacuation. MethodsPorcine TBI was induced via controlled cortical injury. Twenty nonsurvival pigs were separated into four groups (n = 5 each): TBI+25 mL normal saline (NS), TBI+4 mg propranolol, TBI+100 mg allopurinol, and TBI+1g TXA. The pigs then underwent simulated AE to an altitude of 8000 ft for 4 h with an SpO2 of 82-85% and were sacrificed 4 h later. Hemodynamics, serum cytokines, and hippocampal p-tau accumulation were assessed. An additional survival cohort was partially completed with TBI/NS (n = 5), TBI/propranolol (n = 2) and TBI/allopurinol groups (n = 2) survived to postinjury day 7. ResultsThere were no significant differences in hemodynamics, tissue oxygenation, cerebral blood flow, or physiologic markers between treatment groups and saline controls. Transient differences in IL-1b and IL-6 were noted but did not persist. Neurological Severity Score (NSS) was significantly lower in the TBI + allopurinol group on POD one compared to NS and propranolol groups. P-tau accumulation was decreased in the nonsurvival animals treated with allopurinol and TXA compared to the TBI/NS group. ConclusionsAllopurinol, propranolol, and TXA, following TBI, do not induce adverse changes in systemic or cerebral hemodynamics during or after a simulated postinjury flight. While transient changes were noted in systemic cytokines and p-tau accumulation, further investigation will be needed to determine any persistent neurological effects of injury, flight, and pharmacologic treatment.

Abstract No. 163 Feasibility of pancreatic particle embolization: a proof of safety study in a porcine model

Although particle embolization is a common treatment of hypervascular neuroendocrine metastases of the liver, this treatment is not considered an option for the originating pancreatic neuroendocrine tumor(s) due to theoretical concern for pancreatitis. The purpose of this study was to explore the safety of pancreatic embolization in a porcine model. Approval for this study was obtained from the Institutional Animal Care and Use Committee. A total of 6 domestic swine weighing between 90 and 110 pounds were obtained. A single nonsurvival animal underwent infusion of methylene blue dye into the dorsal pancreatic artery using a microcatheter followed by particle embolization to stasis using 100-300 μm Embosphere particles to confirm technical feasibility. Immediate laparotomy confirmed blue staining of pancreatic parenchyma without evidence of non-target embolization. Five survival animals underwent baseline serum lipase level assay, and particle embolization of the dorsal pancreatic artery was performed under general anesthesia. Animals were observed postoperatively for one week with monitoring of behavior, activity, food intake, and observation for signs of pancreatitis. After one week, repeat serum lipase was obtained, the animals were euthanized, and their pancreata excised for gross pathologic analysis. Technical success with embolization was achieved in all study animals. In the five survival animals that were monitored after embolization, behavior, activity levels and food intake returned to baseline by postoperative day #1. All animals survived to 7 days without signs or symptoms of significant pain, systemic infection or decline. There was no significant change in serum lipase levels comparing pre-procedure to day 7, with average serum lipase levels of 56.8 U/L and 40.2 U/L, respectively. At necropsy, regions of lobular expansion and discoloration were identified in all pancreata that are compatible with inflammation. These findings suggest that particle embolization of the dorsal pancreatic artery in swine is technically feasible and results in adequate ischemia to cause inflammation of target pancreatic tissues, but without biochemical signs of pancreatitis, systemic sequelae, or mortality after one week of observation. Based on this early data, further evaluation of particle embolization of the pancreas in animal models may be justified to further clarify safety and physiologic sequelae.

Bacteriophages Improve Outcomes in Experimental Staphylococcus aureus Ventilator-associated Pneumonia.

Rationale: Infections caused by multidrug-resistant bacteria are a major clinical challenge. Phage therapy is a promising alternative antibacterial strategy.Objectives: To evaluate the efficacy of intravenous phage therapy for the treatment of ventilator-associated pneumonia due to methicillin-resistant Staphylococcus aureus in rats.Methods: In a randomized, blinded, controlled experimental study, we compared intravenous teicoplanin (3 mg/kg, n = 12), a cocktail of four phages (2-3 × 109 plaque-forming units/ml of 2003, 2002, 3A, and K; n = 12), and a combination of both (n = 11) given 2, 12, and 24 hours after induction of pneumonia, and then once daily for 4 days. The primary outcome was survival at Day 4. Secondary outcomes were bacterial and phage densities in lungs and spleen, histopathological scoring of infection within the lungs, and inflammatory biomarkers in blood.Measurements and Main Results: Treatment with either phages or teicoplanin increased survival from 0% to 58% and 50%, respectively (P < 0.005). The combination of phages and antibiotics did not further improve outcomes (45% survival). Animal survival correlated with reduced bacterial burdens in the lung (1.2 × 106 cfu/g of tissue for survivors vs. 1.2 × 109 cfu/g for nonsurviving animals; P < 0.0001), as well as improved histopathological outcomes. Phage multiplication within the lung occurred during treatment. IL-1β increased in all treatment groups over the course of therapy.Conclusions: Phage therapy was as effective as teicoplanin in improving survival and decreasing bacterial load within the lungs of rats infected with methicillin-resistant S. aureus. Combining antibiotics with phage therapy did not further improve outcomes.

Comparing regression, naive Bayes, and random forest methods in the prediction of individual survival to second lactation in Holstein cattle

In this study, we compared multiple logistic regression, a linear method, to naive Bayes and random forest, 2 nonlinear machine-learning methods. We used all 3 methods to predict individual survival to second lactation in dairy heifers. The data set used for prediction contained 6,847 heifers born between January 2012 and June 2013, and had known survival outcomes. Each animal had 50 genomic estimated breeding values available at birth and up to 65 phenotypic variables that accumulated over time. Survival was predicted at 5 moments in life: at birth, at 18 mo, at first calving, at 6 wk after first calving, and at 200 d after first calving. The data sets were randomly split into 70% training and 30% testing sets to evaluate model performance for 20-fold validation. The methods were compared for accuracy, sensitivity, specificity, area under the curve (AUC) value, contrasts between groups for the prediction outcomes, and increase in surviving animals in a practical scenario. At birth and 18 mo, all methods had overlapping performance; no method significantly outperformed the other. At first calving, 6 wk after first calving, and 200 d after first calving, random forest and naive Bayes had overlapping performance, and both machine-learning methods outperformed multiple logistic regression. Overall, naive Bayes has the highest average AUC at all decision points up to 200 d after first calving. Random forest had the highest AUC at 200 d after first calving. All methods obtained similar increases in survival in the practical scenario. Despite this, the methods appeared to predict the survival of individual heifers differently. All methods improved over time, but the changes in mean model outcomes for surviving and non-surviving animals differed by method. Furthermore, the correlations of individual predictions between methods ranged from r = 0.417 to r = 0.700; the lowest correlations were at first calving for all methods. In short, all 3 methods were able to predict survival at a population level, because all methods improved survival in a practical scenario. However, depending on the method used, predictions for individual animals were quite different between methods.

The Cytokine Response Profile of Ebola Virus Disease in a Large Cohort of Rhesus Macaques Treated With Monoclonal Antibodies.

Ebola virus (EBOV) is a highly pathogenic filovirus that causes outbreaks of a severe hemorrhagic fever known as EBOV disease (EVD). Ebola virus disease is characterized in part by a dysregulated immune response and massive production of both pro- and anti-inflammatory cytokines. To better understand the immune response elicited by EVD in the context of treatment with experimental anti-EBOV antibody cocktails, we analyzed 29 cytokines in 42 EBOV-infected rhesus macaques. In comparison to the surviving treated animals, which exhibited minimal aberrations in only a few cytokine levels, nonsurviving animals exhibited a dramatically upregulated inflammatory response that was delayed by antibody treatment.

Fetal Mouse Cardiovascular Imaging Using a High-frequency Ultrasound (30/45MHZ) System.

Congenital heart defects (CHDs) are the most common cause of childhood morbidity and early mortality. Prenatal detectionof the underlying molecular mechanisms of CHDs iscrucial for inventing new preventive and therapeutic strategies. Mutant mouse models are powerful tools to discover newmechanismsand environmental stress modifiers that drive cardiac development and their potentialalteration in CHDs. However, efforts to establish the causality of these putative contributors have been limited to histologicaland molecular studiesin non-survival animal experiments, in whichmonitoring the key physiological and hemodynamic parameters isoften absent. Live imaging technology has become an essential tool to establish theetiology of CHDs. In particular,ultrasound imaging can be used prenatally without surgically exposing the fetuses,allowing maintainingtheir baseline physiology while monitoring the impact of environmental stresson the hemodynamic and structural aspects of cardiac chamber development. Herein, we use the High-Frequency Ultrasound (30/45)system to examine the cardiovascular system in fetal mice at E18.5 in utero at the baseline and in response to prenatal hypoxia exposure. We demonstrate the feasibility of the system to measure cardiac chamber size, morphology, ventricular function, fetal heart rate, and umbilical artery flow indices, and their alterations in fetal mice exposed to systemic chronic hypoxia in utero in real time.

On-pump transapical cardioscopic mitral valve replacement with cardiac arrest: short-term results in a porcine survival model.

Favourable outcomes with mitral annuloplasty have been achieved with transapical cardioscopic (TAC) surgery in a survival animal model. In addition, experimental TAC on a non-survival animal model also showed adequate access to remove the native mitral valve and implant a prosthetic valve, but the surgical procedure took a long time and lacked follow-up data. The goal of this study was to develop a clinically translatable TAC mitral valve replacement (MVR) procedure using technical and instrumental refinements to reduce the surgical time and to evaluate functional recovery and short-term durability using a survival porcine model. We hypothesized that MVR could be achieved with subannular implantation of the bioprosthesis via the TAC approach. TAC MVR using the Hancock II™ (Medtronic)® mitral prosthesis was performed in 6 pigs via an incision over the xiphoid process, under cardiopulmonary bypass and cardiac arrest. COR-KNOT® and minimally invasive cardiac surgery instruments were used. Haemodynamics, echocardiography, cardiac computed tomography, ventriculography and electrocardiography were used to evaluate the function of the mitral prosthesis and left ventricle, coronary system and conduction system in the perioperative period and 4 weeks later. A postimplant examination showed that the mitral prosthesis was competent, without a paravalvular leak. The left ventricular ejection fraction was comparable to preoperative values (65.2 ± 4.1 vs 67.2 ± 7.9). The bypass, cross-clamp and implant times were 177.2 ± 44.2 min, 135.3 ± 47.6 min and 94.0 ± 41.2 min, respectively. The prosthesis was in a good position. The apical scar was intact and not aneurysmal 4 weeks after the implant. The valve was properly sutured to the annulus, without a postimplant paravalvular leak. All animals recovered after 1 month of follow-up with preserved ventricular function and normal wall motion. We successfully managed to replace the mitral valve with a biological prosthesis via the apex with encouraging bypass and cross-clamp times. This technique may provide an alternative for a selected group of patients with diseased mitral valves who have indications for MVR and still in a high-risk redo setting with conventional sternotomy or minimally invasive cardiac surgery-MVR.

GalT-KO pig lungs are highly susceptible to acute vascular rejection in baboons, which may be mitigated by transgenic expression of hCD47 on porcine blood vessels.

Despite recent progress in survival times of xenografts in non-human primates, there are no reports of survival beyond 5days of histologically well-aerated porcine lung grafts in baboons. Here, we report our initial results of pig-to-baboon xeno-lung transplantation (XLTx). Eleven baboons received genetically modified porcine left lungs from either GalT-KO alone (n=3), GalT-KO/humanCD47(hCD47)/hCD55 (n=3), GalT-KO/hD47/hCD46 (n=4), or GalT-KO/hCD39/hCD46/hCD55/TBM/EPCR (n=1) swine. The first 2 XLTx procedures were performed under a non-survival protocol that allowed a 72-hour follow-up of the recipients with general anesthesia, while the remaining 9 underwent a survival protocol with the intention of weaning from ventilation. Lung graft survivals in the 2 non-survival animals were 48 and >72hours, while survivals in the other 9 were 25 and 28hours, at 5, 5, 6, 7, >7, 9, and 10days. One baboon with graft survival >7days, whose entire lung graft remained well aerated, was euthanized on POD 7 due to malfunction of femoral catheters. hCD47 expression of donor lungs was detected in both alveoli and vessels only in the 3 grafts surviving >7, 9, and 10days. All other grafts lacked hCD47 expression in endothelial cells and were completely rejected with diffuse hemorrhagic changes and antibody/complement deposition detected in association with early graft loss. To our knowledge, this is the first evidence of histologically viable porcine lung grafts beyond 7days in baboons. Our results indicate that GalT-KO pig lungs are highly susceptible to acute humoral rejection and that this may be mitigated by transgenic expression of hCD47.

Treatment with 24\xa0h\u2013delayed normo- and hyperbaric oxygenation in severe sepsis induced by cecal ligation and puncture in rats

BackgroundSeptic shock remains a leading cause of death worldwide. Hyperbaric oxygen treatment (HBO2) has been shown to alter the inflammatory response during sepsis and to reduce mortality. A therapeutic window of HBO2 treatment has been demonstrated experimentally, but optimal timing remains uncertain. We investigated the effects of 24 h delayed normobaric oxygen (NBO2) and HBO2 treatment on the endogenous production of the inflammatory markers interleukin (IL)-6, tumor necrosis factor (TNF)-α and IL-10, and on mortality in rats with cecal ligation and puncture (CLP) induced sepsis.MethodFifty-five male Sprague-Dawley rats underwent CLP and were randomized to the following groups: 1) HBO2 2.5 bar absolute pressure (pabs); 2) NBO2 1.0 bar pabs; 3) Control (no-treatment), and they were individually monitored for 72 h with intermittent blood sampling.ResultsIL-6, TNF-α, and IL-10 were increased 24 h after the procedure, and IL-6 was significantly higher in non-survivors than in survivors. The level of IL-10 was significantly higher at hour 48 in the HBO2 group compared to control (p = 0.01), but this was not the case at other time points. No other significant differences in cytokine levels were found for any group comparisons. Delayed NBO2 and HBO2 treatment failed to change the mortality in the animals.ConclusionHigh levels of IL-6 in non-surviving animals with sepsis suggest that IL-6 is a potential biomarker. We found a significantly higher concentration of IL-10 in the HBO2 group at hour 48 vs. control animals. However, 24 h–delayed treatment with HBO2 did not change the levels of pro-inflammatory cytokines and survival, suggesting that earlier intervention may be required to obtain an anti-inflammatory effect.

Coronary fat embolism following subarachnoid hemorrhage: an experimental study.

Subarachnoid hemorrhage (SAH) can lead to neurogenic pulmonary edema (NPE), and chylomicron metabolism may be altered unfavorably in acute lung injury. This study aimed to investigate the possible effect of NPE on the development of coronary fat embolism. This study was conducted on 27 rabbits, 5 of which were used as the control (n=5). Experimental SAH was induced in 15 of the animals by injecting homologous blood into the cisterna magna, and the remaining 7 animals were administered only isotonic saline solution (Sham, n=7) in the same manner under general anesthesia. After 21 days, all the animals were euthanized, and their hearts, lungs, and brains underwent histopathological examination. Six animals died of SAH during the experiment, and foamy hemorrhagic parenchymal lesions and intra-alveolar hemorrhage were observed in their lungs. The histopathologic findings revealed minimal changes in the lungs, heart, and brains of the surviving animals; however, an abundant amount of fat globules was found in the coronary arteries of the six nonsurviving animals. There was a meaningful difference between the number of occluded coronary arteries with fatty globules in the surviving and nonsurviving animals (P<.001). However, the difference between the survivors and the isotonic-saline-injected group was not meaningful (P>.05). Coronary fat embolism was an important mortality factor following SAH (P<.005). In SAH-induced NPE, the leakage of chylomicrons into the systemic circulation may lead to coronary fat embolism, which has not yet been reported in the literature.

Suburothelial Bladder Contraction Detection with Implanted Pressure Sensor.

AimsManaging bladder pressure in patients with neurogenic bladders is needed to improve rehabilitation options, avoid upper tract damage, incontinence, and their associated co-morbidities and mortality. Current methods of determining bladder contractions are not amenable to chronic or ambulatory settings. In this study we evaluated detection of bladder contractions using a novel piezoelectric catheter-free pressure sensor placed in a suburothelial bladder location in animals.MethodsWired prototypes of the pressure monitor were implanted into 2 nonsurvival (feline and canine) and one 13-day survival (canine) animal. Vesical pressures were obtained from the device in both suburothelial and intraluminal locations and simultaneously from a pressure sensing catheter in the bladder. Intravesical pressure was monitored in the survival animal over 10 days from the suburothelial location and necropsy was performed to assess migration and erosion.ResultsIn the nonsurvival animals, the average correlation between device and reference catheter data was high during both electrically stimulated bladder contractions and manual compressions (r = 0.93±0.03, r = 0.89±0.03). Measured pressures correlated strongly (r = 0.98±0.02) when the device was placed in the bladder lumen. The survival animal initially recorded physiologic data, but later this deteriorated. However, endstage intraluminal device recordings correlated (r = 0.85±0.13) with the pressure catheter. Significant erosion of the implant through the detrusor was found.ConclusionsThis study confirms correlation between suburothelial pressure readings and intravesical bladder pressures. Due to device erosion during ambulatory studies, a wireless implant is recommended for clinical rehabilitation applications.

Citric Acid Cycle Metabolites Predict the Severity of Myocardial Stunning and Mortality in Newborn Pigs.

Myocardial infarction and chronic heart failure induce specific metabolic changes in the neonatal myocardium that are closely correlated to outcome. The aim of this study was to examine the metabolic responses to noninfarct heart failure and inotropic treatments in the newborn heart, which so far are undetermined. A total of 28 newborn pigs were instrumented with a microdialysis catheter in the right ventricle, and intercellular citric acid cycle intermediates and adenosine metabolite concentrations were determined at 20-minute intervals. Stunning was induced by 10 cycles of 3 minutes of ischemia, which was performed by occluding the right coronary artery, followed by 3 minutes of reperfusion. Animals were randomized for treatment with epinephrine + milrinone, dopamine + milrinone, dobutamine, or saline. University hospital animal laboratory. Ischemia-reperfusion induced right ventricular stunning and increased the concentrations of pyruvate lactate, succinate, malate, hypoxanthine, and xanthine (all, p < 0.01). During inotrope infusion, no differences in metabolite concentrations were detected between the treatment groups. In nonsurviving animals (n = 8), concentrations of succinate (p < 0.0001), malate (p = 0.009), and hypoxanthine (p = 0.04) increased compared with survivors, while contractility was significantly reduced (p = 0.03). Accumulation of citric acid cycle intermediates and adenosine metabolites reflects the presence of myocardial stunning and predicts mortality in acute noninfarct right ventricular heart failure in newborn pigs. This phenomenon occurs independently of the type of inotrope, suggesting that citric acid cycle intermediates represent potential markers of acute noninfarct heart failure.

Control of severe intra-abdominal hemorrhage with an infusible platelet-derived hemostatic agent in a nonhuman primate (rhesus macaque) model.

Hemorrhage remains the leading cause of potentially survivable trauma mortality. Recent reports indicate that injuries sustained in noncompressible anatomic locations (i.e., truncal and junctional) account for 86.5% of hemorrhage-related deaths. Infusible human platelet-derived hemostatic agents (hPDHAs) represent a promising strategy to reduce blood loss from noncompressible injuries. Here, we evaluate the hemostatic efficacy of a lyophilized hPDHA in a rhesus macaque model of severe, uncontrolled hemorrhage. Hemorrhage was induced via laparoscopic 60% left-lobe hepatectomy in anesthetized rhesus macaques (T = 0 minute). Treatment infusion began with an 11-mL bolus (T = 5-6 minutes) of either 5% albumin solution (control; n = 8) or hPDHA (1.2 × 10(10) platelet equivalents, n = 8), followed by 2.8-mL/min 0.9% normal saline at T = 6-20 minutes. Resuscitation continued with normal saline (0.22 mL/kg/min) to a total volume of 20 mL/kg at T = 120 minutes, at which time surgical hemostasis was achieved and percent blood loss quantified. Animals were monitored until T = 480 minutes and then euthanized, and necropsy was performed with emphasis on intravascular and end-organ thrombi. Data are expressed as mean ± SEM; significance, p < 0.05. Both groups exhibited a ∼70% decrease in mean arterial pressure (MAP) from T = 0-5 minutes. Percent blood loss was 44.2 ± 3.9% in hPDHA animals, and 44.3 ± 3.3% in controls. Survival rates were 4 of 8 for hPDHA animals and 7 of 8 for controls. Regardless of treatment, percent blood loss was greater (p < 0.02) in nonsurviving animals (55 ± 2%, n = 5) compared with surviving animals (42% ± 3%, n = 11). No pathologic intravascular thrombi were observed in either group. The isolated administration of hPDHA did not significantly reduce blood loss; however, thrombocytopenia was not present in the model, and clinically, platelets would be administered in combination with plasma. Mortality was not statistically different between groups (p = 0.14) but was related to blood loss. Future studies should consider the use of hPDHA in combination with additional therapeutics (e.g., factors) and a model that incorporates thrombocytopenia or platelet dysfunction.

Heart Rate Variability Analysis in an Experimental Model of Hemorrhagic Shock and Resuscitation in Pigs.

BackgroundThe analysis of heart rate variability (HRV) has been shown as a promising non-invasive technique for assessing the cardiac autonomic modulation in trauma. The aim of this study was to evaluate HRV during hemorrhagic shock and fluid resuscitation, comparing to traditional hemodynamic and metabolic parameters.MethodsTwenty anesthetized and mechanically ventilated pigs were submitted to hemorrhagic shock (60% of estimated blood volume) and evaluated for 60 minutes without fluid replacement. Surviving animals were treated with Ringer solution and evaluated for an additional period of 180 minutes. HRV metrics (time and frequency domain) as well as hemodynamic and metabolic parameters were evaluated in survivors and non-survivors animals.ResultsSeven of the 20 animals died during hemorrhage and initial fluid resuscitation. All animals presented an increase in time-domain HRV measures during haemorrhage and fluid resuscitation restored baseline values. Although not significantly, normalized low-frequency and LF/HF ratio decreased during early stages of haemorrhage, recovering baseline values later during hemorrhagic shock, and increased after fluid resuscitation. Non-surviving animals presented significantly lower mean arterial pressure (43±7vs57±9 mmHg, P<0.05) and cardiac index (1.7±0.2vs2.6±0.5 L/min/m2, P<0.05), and higher levels of plasma lactate (7.2±2.4vs3.7±1.4 mmol/L, P<0.05), base excess (-6.8±3.3vs-2.3±2.8 mmol/L, P<0.05) and potassium (5.3±0.6vs4.2±0.3 mmol/L, P<0.05) at 30 minutes after hemorrhagic shock compared with surviving animals.ConclusionsThe HRV increased early during hemorrhage but none of the evaluated HRV metrics was able to discriminate survivors from non-survivors during hemorrhagic shock. Moreover, metabolic and hemodynamic variables were more reliable to reflect hemorrhagic shock severity than HRV metrics.

Significance of clinical variables and selected biochemical markers in predicting the outcome of bovine anaplasmosis

The present study was aimed at evaluating the usefulness of selected inflammatory and oxidative stress markers in predicting the clinical outcome of cattle infected with Anaplasma (A). marginale. The study population consisted of 39 cattle naturally infected with A. marginale. The presumptive diagnosis of this infection was initially achieved on the basis of case history, microscopy and clinical examination findings, and confirmed using A. marginale-specific PCR assays. The diseased cattle were categorised according to the clinical outcome into survivors (n = 26) and non-survivors (n = 13). For comparison, ten clinically healthy cattle were randomly selected and served as controls. Blood was drawn from all examined animals to measure the respective levels of selected cytokines, acute phase proteins, oxidative stress markers, and antioxidant enzyme levels. We found that the clinical examination alone was not conclusive and should be used in conjunction with other diagnostic methods. Nonetheless, the non-surviving animals showed anorexia, frequent coughing, dyspnoea, bloody faeces, recumbency, pale or icteric mucous membranes, and haemoglobinuria. Biochemically, tumour necrosis factor alpha, interleukin (IL)-1β, IL-6, serum amyloid A, fibrinogen, malondialdehye, superoxide dismutase, and catalase levels were significantly higher in diseased cattle compared with controls, and were higher in non-survivors than survivors (P < 0.05). In contrast, reduced glutathione (G-SH) was significantly lower in non-surviving cattle than survivors and controls. Interestingly, a significant correlation was found between parasitaemia of the diseased cattle and most of the measured biochemical variables, with IL-1β and G-SH showing the highest correlation. Our findings clearly demonstrate that A. marginale infection is associated with marked inflammatory and oxidative stress responses, which are higher in non-surviving cattle compared with survivors. The overall degree of cytokine and anti-oxidative disruption may have an important prognostic value for the disease outcome.

Improvements and innovations in endoscopic ultrasound guided fine needle aspiration.

Keywords: Algorithm; Core histology needle; Cytology; Endoscopic ultrasound guided fine needle aspiration fine needle biopsy; Histology

Cardiopulmonary Arrest and Resuscitation in Severe Sepsis and Septic Shock: A Research Model.

Cardiopulmonary resuscitation in patients with severe sepsis and septic shock is challenging and usually unsuccessful. The aim of the present study is to describe our swine model of cardiac arrest and resuscitation in severe sepsis and septic shock. In this prospective randomized animal study, 10 healthy female Landrace-Large White pigs with an average weight of 20 ± 1 kg (aged 19 - 21 weeks) were the study subjects. Septicemia was induced by an intravenous infusion of a bolus of 20-mL bacterial suspension in 2 min, followed by a continuous infusion during the rest of the experiment. After septic shock was confirmed, the animals were left untreated until cardiac arrest occurred. All animals developed pulseless electrical activity between the fifth and sixth hours of septicemia, whereas five (50%) of 10 animals were successfully resuscitated. Coronary perfusion pressure was statistically significantly different between surviving and nonsurviving animals. We found a statistically significant correlation between mean arterial pressure and unsuccessful resuscitation (P = 0.046), whereas there was no difference in end-tidal carbon dioxide (23.05 ± 1.73 vs. 23.56 ± 1.70; P = 0.735) between animals with return of spontaneous circulation and nonsurviving animals. During the 45-min postresuscitation monitoring, we noted a significant decrease in hemodynamic parameters, although oxygenation indices and lactate clearance were constantly increased (P = 0.001). This successful basic swine model was for the first time developed and may prove extremely useful in future studies on the periarrest period in severe sepsis and septic shock.