Federica Pirrone

Expression of endothelin-1 system in a pig model of endotoxic shock

Endothelin (ET)-1 is a potent vasoconstrictive peptide and it is involved in the pathogenesis of septic shock. Blockade of ET-1 receptors abolishes the LPS-induced pulmonary hypertension and worsens the LPS-dependent systemic hypotension, but the role of ET-1 in sepsis remains uncertain. To determine the role of ET-1 in cardiovascular and respiratory derangement in a porcine model of endotoxemic shock we evaluated ET-1 plasma levels and ET-1 mRNA and protein levels in lung, liver, and heart as well as Endothelin Converting Enzyme-1, ET(A) and ET(B) receptors mRNA in the same tissues. Twelve piglets were randomised to sham operated or to LPS-treated (40 microg/kg/h for 4 h) groups. During the experiment, respiratory and circulatory parameters have been recorded and blood samples collected. At the end of the experiment the animals were sacrificed and tissue samples collected for real-time quantitative PCR and ELISA test. LPS infusion evokes a large increase in ET-1 plasma concentration, and in tissues mRNA levels, associated with an increase in pulmonary arterial pressure, as well as in pulmonary and systemic vascular resistances, and a decrease in stroke volume. LPS infusion caused also a derangement of respiratory mechanics, evidenced by an increase in resistance and a decrease in compliance of the respiratory system. ET(A) and ET(B) receptor mRNA levels were markedly decreased in liver and lung and slightly increased in heart, evidencing that ET receptor subtypes were differentially regulated in the major organs of endotoxin treated pigs. In conclusion our data show the presence of a continuative and differentially regulated stimulating mechanism of ET-1 expression during pig endotoxaemia as well as a fundamental role of ET-1 system in the cardiovascular and respiratory derangement.

Regional blood acidification enhances extracorporeal carbon dioxide removal: a 48-hour animal study

Background:Extracorporeal carbon dioxide removal has been proposed to achieve protective ventilation in patients at risk for ventilator-induced lung injury. In an acute study, the authors previously described an extracorporeal carbon dioxide removal technique enhanced by regional extracorporeal blood acidification. The current study evaluates efficacy and feasibility of such technology applied for 48 h. Methods:Ten pigs were connected to a low-flow veno-venous extracorporeal circuit (blood flow rate, 0.25 l/min) including a membrane lung. Blood acidification was achieved in eight pigs by continuous infusion of 2.5 mEq/min of lactic acid at the membrane lung inlet. The acid infusion was interrupted for 1 h at the 24 and 48 h. Two control pigs did not receive acidification. At baseline and every 8 h thereafter, the authors measured blood lactate, gases, chemistry, and the amount of carbon dioxide removed by the membrane lung (VCO2ML). The authors also measured erythrocyte metabolites and selected cytokines. Histological and metalloproteinases analyses were performed on selected organs. Results:Blood acidification consistently increased VCO2ML by 62 to 78%, from 79 ± 13 to 128 ± 22 ml/min at baseline, from 60 ± 8 to 101 ± 16 ml/min at 24 h, and from 54 ± 6 to 96 ± 16 ml/min at 48 h. During regional acidification, arterial pH decreased slightly (average reduction, 0.04), whereas arterial lactate remained lower than 4 mEq/l. No sign of organ and erythrocyte damage was recorded. Conclusion:Infusion of lactic acid at the membrane lung inlet consistently increased VCO2ML providing a safe removal of carbon dioxide from only 250 ml/min extracorporeal blood flow in amounts equivalent to 50% production of an adult man.

Extracorporeal carbon dioxide removal through ventilation of acidified dialysate: an experimental study.

BACKGROUND Extracorporeal (EC) carbon dioxide (CO(2)) removal (ECCO(2)R) may be a powerful alternative to ventilation, possibly avoiding the need for mechanical ventilation and endotracheal intubation. We previously reported how an infusion of lactic acid before a membrane lung (ML) effectively enhances ECCO(2)R. We evaluated an innovative ECCO(2)R technique based on ventilation of acidified dialysate. METHODS Four swine were sedated, mechanically ventilated, and connected to a venovenous dialysis circuit (blood flow, 250 ml/min). The dialysate was recirculated in a closed loop circuit including a ML (gas flow, 10 liters/min) and then returned to the dialyzer. In each animal, 4 different dialysis flows (DF) of 200, 400, 600, and 800 ml/min were evaluated with and without lactic acid infusion (2.5 mEq/min); the sequence was completed 3 times. At the end of each step, we measured the volume of CO(2)R by the ML (V(co2)ML) and collected blood and dialysate samples for gas analyses. RESULTS Acid infusion substantially increased V(co2)ML, from 33 ± 6 ml/min to 86 ± 7 ml/min. Different DFs had little effect on V(co2)ML, which was only slightly reduced at DF 200 ml/min. The partial pressure of CO(2) of blood passing through the dialysis filter changed from 60.9 ± 3.6 to 37.1 ± 4.8 mm Hg without acidification and to 32.5 ± 5.3 mm Hg with acidification, corresponding to a pH increase of 0.18 ± 0.03 and 0.03 ± 0.04 units, respectively. CONCLUSIONS Ventilation of acidified dialysate efficiently increased ECCO(2)R of an amount corresponding to 35% to 45% of the total CO(2) production of an adult man from a blood flow as low as 250 ml/min.

In vivo study of the behaviour of matrix metalloproteinases (MMP-2, MMP-9) in mechanical, hypoxic and septic-induced acute lung injury.

In vivo study of the behaviour of matrix metalloproteinases (MMP-2, MMP-9) in mechanical, hypoxic and septic-induced acute lung injury F. Pirrone & C. Pastore & S. Mazzola & M. Albertini Published online: 4 July 2009 # Springer Science + Business Media B.V. 2009

Olfactory detection of cancer by trained sniffer dogs: A systematic review of the literature

ABSTRACT Early diagnosis of cancer using effective screening methods is crucial for successful treatment. Recently, much attention has been given to the use of odors emitted in the form of volatile organic compounds as diagnostic biomarkers. Studies on special training of dogs to detect different cancers using various odor samples (breath, urine, cancer tissue) have provided promising results. This systematic review highlights the scientific reports testing canine olfaction to detect cancer, dividing them according to the cancers primary site. Several lines of evidence suggest that dogs may play a critical role in cancer research and diagnosis, eventually be major contributors to a reduction in mortality for certain cancers. Future directions that this field of research should take include efforts to overcome some methodological weaknesses and a certain heterogeneity of performance found across the different studies. Finding adequate responses to the challenges that lie ahead requires also a clear disclosure of what chemical compounds dogs respond to and the quantity of these compounds. Finally, the welfare of dogs involved in these practices should be considered.

ELECTRON SPIN RESONANCE AND CHEMILUMINESCENCE ANALYSES TO ELUCIDATE THE VASODILATING MECHANISM OF SODIUM NITROPRUSSIDE

The aim of this study was to elucidate the vasodilating mechanism of sodium nitroprusside (SNP). To do this, SNP was intravenously infused in pigs (1.67 μmol/kg), and the following paramagnetic metabolites were identified by electron spin resonance: 1) nitrosylhemoglobin [HbFe(II)NO] as an index of the bioconservative pathway; 2) transferrin; 3) [Fe(II)(CN)5 NO]3- and [Fe(II)(CN)4 NO]2-, the reduced penta- and tetracoordinated intermediates of SNP, respectively; and 4) methemoglobin (met-Hb). The results indicate the following: 1) ≈17% of the dose is converted to HbFe(II)NO at the end of infusion; 2) NO administered as SNP does not undergo bioinactivation (oxidative metabolism), because no significant increase of met-Hb was observed; 3) the equilibrium involving the paramagnetic species of SNP is shifted toward HbFe(II)NO, because a significant increase of transferrin but no detection of the reduced paramagnetic intermediates of SNP was observed. The results obtained indicate that the hemodynamic effect induced by SNP is not mediated by HbFe(II)NO, at least under physiological conditions; hence, a direct release of NO from SNP in the vascular target should be considered. To demonstrate this mechanism, endothelial cells were incubated with SNP, and the release of NO was determined by a novel chemiluminescence method. The results indicate that the endothelium is able to metabolize SNP, with the formation of stoichiometric amounts of NO. In conclusion, SNP is rapidly metabolized to HbFe(II)NO, but the pharmacological response is mediated by a direct mechanism of NO release of the parent compound at the cellular target.

Role of the Endothelium in the Biotransformation of Sodium Nitroprusside (SNP): In vivo and In vitro Study

INTRODUCTIONNitric oxide is a critical regulator of endothelial functions and vascular smooth muscletone. In a previous work, we demonstrated that under physiological conditions NO in-fusion markedly raises the formation of bioactive molecules, such as nitrosylhemoglobin[HbFe(II)NO], without evoking significant hemodynamic responses (Aldini

Tail Chasing in a Dog With Brain Atrophy: a Case Report

ABSTRACT A 2‐year‐old male mixed breed sheepdog was presented with a history of worsening recurrent tail chasing (TC) and biting by 2 months of age. Physical examination and blood tests showed no health problems, except for mild leukocytosis. Behavior analysis excluded the presence of other compulsive behaviors, but aggressive behavior during TC was reported. Neurological examination showed aggressive behavior in a dog that was otherwise quiet until few months before the consultation. A forebrain disorder such as a congenital or a degenerative disease could not be ruled out. In vivo computed tomography brain scan revealed widened sulci and symmetrical lateral ventricular enlargement, which were associated with cerebral atrophy with acquisition of contrast enhancement. A diagnosis of brain atrophy probably due to a degenerative disease was made. After 5 days, the dog was euthanized following the owners request due to deteriorating condition. In dogs showing repetitive and potentially compulsive disorders, veterinarians should be aware that a structural disorder as a brain atrophy should be included in differentials.

Activated protein C protection from lung inflammation in endotoxin-induced injury.

We studied the protection of recombinant human activated protein C (rhAPC) in endotoxin-induced lung inflammation and injury and whether this effect is correlated with modulation of lung matrix metalloproteinase (MMP) activity. We randomly assigned 12 Large White pigs to receive intravenous Escher-ichia coli lipopolysaccharide (LPS; 40 μ g/kg/hr), rhAPC (24 μ g/ kg/hr), or both. We monitored respiratory mechanics and function, cell counts, and cytokine concentrations in bron-choalveolar lavage fluid (BALF). Lung samples were collected for the zymography of MMP-2 and MMP-9 activities and for histology. In septic pigs, rhAPC decreased proMMP-9 release as well as MMP-9 activation, and increased proMMP-2 presence without any evident activation compared with specimens that were given LPS alone. In addition, lung injury in rhAPC-treated animals was significantly attenuated, as shown by higher respiratory compliance, delayed increase in tumor necrosis alfa and interleukin-1β as well as neutrophil recruitment in the BALF, reduced lung edema, and histologic changes. In conclusion, rhAPC is beneficial in acute lung injury, and the protection may depend, at least in part, on modulation of MMP-2/9 activity.

Different dynamics of sensory-motor development and behavior during the transitional period in puppies : preliminary results

Abstract Many studies have analyzed the behavior of puppies during their socialization period, while little attention has been paid to the transitional period, when vision and hearing develop. Here, we compared the average age of sensory and motor development, and the behavior among a total of 25 puppies. Each litter was videotaped during 1-hour daily sessions on postnatal days 10-21 and coded for the following mutually exclusive behavioral categories: sleeping, suckling and moving. The moving category included side-to-side head swinging, exploring, rolling and allogrooming. The opening of the eyelids, appearance of the startle response and ability to stand up with either the front or hind legs were identified. The duration and frequency of puppy behaviors varied significantly with breed and season of birth. Breed and gender differences in gross motor and sensory development were also observed. These findings may turn out to be crucial to enhance the welfare, standards of rearing, and behavioral interventions aimed at improving adaptability to novel stimuli in pet dogs.