Luigi Intorre

Acute toxicity of ionic liquids to the zebrafish (Danio rerio)

Acute toxicity and histological damage derived from exposure of Danio rerio (zebrafish) to several ionic liquids have been evaluated.

Pharmacokinetics of enrofloxacin in the seabass (Dicentrarchus labrax)

Abstract The plasma kinetics and tissue distribution of enrofloxacin (EF) were investigated in the seabass (Dicentrarchus labrax) after administration by oral gavage and by bath. Plasma and tissue concentrations of EF and of its metabolite ciprofloxacin (CF) were determined by HPLC. After oral treatment (5 mg/kg bw), EF was slowly absorbed and eliminated (Cmax=1.39±0.67 μg/ml at 8 h; T1/2=25 h). EF was distributed efficiently to the extravascular compartment, with concentrations in liver constantly higher than in muscle and skin. Bath treatment (5, 10 or 50 ppm for 4, 8 or 24 h) resulted in plasma and tissue levels that significantly correlated with water drug concentration or time of exposure to medicated water. CF was detected constantly in liver, occasionally in plasma, but never in muscle and skin, suggesting a low degree of metabolic conversion of EF in the seabass. After oral treatment at 5 mg/kg and bath treatment at 50 ppm for 4 h or at 5 ppm for 24 h, ratios between EF peak concentrations in plasma and tissues and MICs of EF against the most common fish pathogens exceeded those indicated as optimal to ensure the bactericidal efficacy of the drug. These dosages of EF are proposed for performing therapeutic trials in the seabass.

An optimized digestion method coupled to electrochemical sensor for the determination of Cd, Cu, Pb and Hg in fish by square wave anodic stripping voltammetry

An optimized digestion method coupled to electrochemical detection to monitor lead, copper, cadmium and mercury in fish tissues was developed. Square wave anodic stripping voltammetry (SWASV) coupled to disposable screen-printed electrodes (SPEs) was employed as fast and sensitive electroanalytical method for heavy metals detection. Different approaches in digestion protocols were assessed. The study was focused on Atlantic hake fillets because of their wide diffusion in the human nutrition. Best results were obtained by digesting fish tissue with hydrogen peroxide/hydrochloric acid mixture coupled to solid phase (SP) purification of the digested material. This combined treatment allowed quantitative extraction from fish tissue (muscle) of the target analytes, with fast execution times, high sensitivity and avoiding organic residues eventually affecting electrochemical measurements. Finally, the method has been validated with reference standard materials such as dogfish muscle (DORM-2) and mussel tissues (NIST 2977).

THE PLASMA KINETICS AND TISSUE DISTRIBUTION OF ENROFLOXACIN AND ITS METABOLITE CIPROFLOXACIN IN THE MUSCOVY DUCK

Intorre, L., Mengozzi, G., Bertini, S., Bagliacca, M., Luchetti, E. and Soldani, G., 1997. The plasma kinetics and tissue distribution of enrofloxacin and its metabolite ciprofloxacin in the Muscovy duck. Veterinary Research Communications, 21 (2), 127-136

Antimicrobial susceptibility of Staphylococcus intermedius and Staphylococcus schleiferi isolated from dogs.

The susceptibility to 23 antimicrobial agents was determined in 114 isolates of Staphylococcus intermedius and eight isolates of Staphylococcus schleiferi of canine origin. Overall, 73% of S. intermedius isolates and 37.5% of S. schleiferi isolates were susceptible to all the 23 antimicrobials tested. The large majority of S. intermedius strains retained susceptibility to antimicrobials currently employed in treatment of pyoderma (cephalosporins, cotrimoxazole and association amoxicillin-clavulanic acid) as well as to those effective against staphylococci (fusidic acid, rifampicin and fluoroquinolones). Resistance in S. intermedius was observed mainly against macrolides, chloramphenicol and lincosamides, while S. schleiferi isolates retained susceptibility to all antimicrobials except three of six fluoroquinolones. Although, our results confirm susceptibility to antimicrobials currently employed in pyoderma treatment, the several different resistance patterns observed for S. intermedius emphasize the importance of antimicrobial susceptibility testing of canine staphylococci to choose the most appropriate treatment of infections and to allow the prudent use of antimicrobial drugs in companion animals.

AN ANALYSIS OF THE EFFECTS OF GALANIN ON GASTRIC-ACID SECRETION AND PLASMA-LEVELS OF GASTRIN IN THE DOG

The effects of galanin on gastric acid secretion and plasma levels of gastrin were studied in conscious dogs chronically fitted with gastric fistulas. Continuous i.v. infusion of galanin (2 micrograms.kg-1.h-1) for 2 h did not affect unstimulated total acid output or plasma levels of gastrin. In contrast, simultaneous i.v. infusion of galanin (1-2 micrograms.kg-1.h-1) inhibited the bombesin-stimulated output of acid whereas the effects of bombesin on gastrin output were not significantly modified. Galanin (2-4 micrograms.kg-1 i.v.) also depressed the secretory response to 2-deoxy-D-glucose without significantly affecting plasma gastrin levels. Galanin (2-4 micrograms.kg-1 i.v.) did not depress bethanechol-stimulated gastric acid output or inhibit histamine-stimulated gastric acid secretion. These findings indicate that glanin inhibits the bombesin- and 2-deoxy-D-glucose-stimulated secretion of gastric acid in conscious dogs by an action which is probably exerted at the level of the cholinergic nerve terminals.

Antimicrobial resistance of Actinobacillus pleuropneumoniae isolated from swine

The aim of this retrospective study was to evaluate the antimicrobial resistance rates and the trend in resistance of Actinobacillus pleuropneumoniae isolated from pigs in Italy from 1994 to 2009. A total of 992 A. pleuropneumoniae isolates were tested for their susceptibility to a panel of antimicrobial agents in a disk diffusion method. Resistance to 7 drugs (amoxicillin, amoxicillin/clavulanic acid, ampicillin, cefquinome, cotrimoxazole, penicillin G and tilmicosin) showed a significant increasing trend over the time, while for 2 drugs (gentamycin and marbofloxacin) a significant decrease was observed. Resistance to the remaining 14 antimicrobial agents tested did not change significantly over the study period. Most of the isolates retained high susceptibility to antimicrobials usually effective against A. pleuropneumoniae such as amphenicols, fluoroquinolones and ceftiofur. However, high rates of resistance were observed for potentiated sulfa drugs, tetracyclines and penicillins which are currently recommended antimicrobials for pig pleuropneumonia therapy. Our results suggest the importance of continued monitoring of A. pleuropneumoniae clinical isolates in order to choose the most appropriate treatment of infections and to control the increase of resistance to currently used antimicrobials.

Modulation of Pentagastrin-Induced Histamine Release by Histamine H3 Receptors in the Dog

BACKGROUND The histamine H3 receptor has been shown to inhibit pentagastrin-induced gastric acid secretion in dogs. Since pentagastrin releases histamine in dogs, we have now assessed whether the effects of H3-receptor ligands may be indirectly mediated by changes in gastric histamine release. METHODS Pentagastrin infusions (1 or 6 micrograms/kg/h), alone or together with the H3-receptor agonist (R) alpha-methylhistamine (1.2 mumol/kg/h) or the antagonist thioperamide (0.1 mumol/kg/h), were performed in dogs. One group (anaesthetized) was used for enzyme immunoassays of plasma histamine and, when required. (R) alpha-methylhistamine in the gastrosplenic vein, and another group (non-anaesthetized) for measurement of gastric acid secretion. RESULTS Histamine levels were increased five- and eight-fold after 1 and 6 micrograms/kg/h pentagastrin, respectively, whereas acid output was nearly maximal at the lower dosage. (R) alpha-methylhistamine, at a plasma concentration of 0.15 microM, inhibited histamine release by 78% (P < 0.007) and 37% (not significant) and the total acid output by 44% (P < 0.05) and 19% (not significant) after infusion of 1 and 6 micrograms/kg/h pentagastrin, respectively. Thioperamide, together with pentagastrin in low dose, significantly increased histamine release by 212% (P < 0.05), whereas acid output increased by 34% (not significant). CONCLUSIONS The histamine H3 receptor mediates a negative feedback control of pentagastrin-induced release of gastric histamine. It is tonically activated by endogenous histamine after pentagastrin in low dosage. The control of acid secretion by the H3 receptor seems to involve modulation of endogenous histamine release, possibly by means of enterochromaffin-like cells.

Use of antimicrobials in companion animal practice: a retrospective study in a veterinary teaching hospital in Italy

OBJECTIVES To describe the use of antimicrobials in a veterinary teaching hospital for companion animals in Italy, with particular regard to the agreement with recommendations of prudent use METHODS The study was conducted with a retrospective, cross-sectional design. The population under investigation included 18,905 cats and dogs that were referred to the hospital between 2000 and 2007. Two different samples of the clinical paper forms were randomly selected to estimate the prevalence of animals receiving an antimicrobial prescription and to describe the pattern of antimicrobials used in relation to the condition being treated. The proportion of antimicrobials prescribed accomplishing recommendations of prudent use was also estimated, as well as the level of agreement with specific, diagnosis-based guidelines for antimicrobial use. RESULTS Broad-spectrum antimicrobials, including penicillins with β-lactamase inhibitors, first-generation cephalosporins and fluoroquinolones, were the most frequently prescribed compounds. Antimicrobials prescribed with the support of microbiological analyses and susceptibility testing were less than 5%. Among the recommendation of prudent use, the availability of information from laboratory testing had the poorest degree of agreement, while the other evaluated items were accomplished in most of the cases. CONCLUSIONS Our results highlight the need to improve the procedures of antimicrobial prescription in the study setting. This can be achieved by supporting the guidance for antimicrobial use at the local level, with the adoption of specific guidelines, and at the national level with a further implementation of the policies of prudent prescriptions.

HISTAMINE H3 RECEPTOR-MEDIATED INHIBITION OF GASTRIC-ACID SECRETION IN CONSCIOUS DOGS

SummaryThe effect of (R)α-methylhistamine (MH) and thioperamide (selective agonist and antagonist respectively of histamine H3 receptors) was examined in conscious gastric fistula dogs to investigate the role of histamine H3 receptors in the control of basal and stimulated gastric acid secretion. Intravenous infusion of MH at 0.3 and 0.6 μmol/kg/h caused a significant reduction of the 2-deoxy-d-glucose (2-DG)-stimulated acid output, maximal inhibition being 60%. The inhibitory effect of MH was counteracted by thioperamide (0.1 μmol/kg/h), which, by itself, did not modify the 2-DG-induced acid secretion. The increase in plasma gastrin levels induced by 2-DG was not significantly affected either by MH or by thioperamide. Under basal conditions MH (0.3 μmol/kg/h) did not induce any significant change in acid secretion and in plasma gastrin levels; by contrast, thioperamide (0.1 μmol/kg/h) produced a significant increase both in acid output and in plasma gastrin.These results suggest that activation of H3 receptors can exert a negative control in stimulated acid secretion in conscious dogs, when cholinergic pathways to acid secretion are activated by 2-DG; moreover, the slight, but significant, stimulatory effect of thioperamide on basal acid output and basal plasma gastrin may be suggestive for a tonic inhibitory role of H3 receptors in the regulation of basal acid secretion, however, a nonspecific effect of this drug cannot be excluded.