R. Odore

Efficacy of Chlorhexidine against Some Strains of Cultured and Clinically Isolated Microorganisms

The efficacy of chlorhexidine digluconate was determined against some strains of collected and clinically isolated bacteria and fungi. The efficacy was evaluated either by calculating a minimum inhibitory concentration (MIC) or by efficacy trials according to the guidelines of the European Committee for Standardization. The MIC values of chlorhexidine for Staphylococcus aureus, Microsporum gypseum, Microsporum canis and Trichophyton mentagrophytes were 0.625 μg/ml, 12.5 μg/ml, 50 μg/ml and 6.25 μg/ml, respectively. The in vitro efficacy of chlorhexidine was higher against ATCC strains of S. aureus and P. aeruginosa (0.5 mg/ml for 5 min and 0.5 mg/ml for 10 min, respectively) than against clinical isolates (0.5 mg/ml for 15 min and 1 mg/ml for 10 min, respectively). The antiseptic activity of aqueous solutions of chlorhexidine against spores of Bacillus subtilis, Bacillis sfericus and Clostridium perfringens required longer contact times than against the vegetative forms. Nevertheless, 5 mg/ml of chlorhexidine in water–ethanol 20:80 v/v was totally effective against the vegetative forms or spores of these microorganisms.

A study to compare circulating flunixin, meloxicam and gabapentin concentrations with prostaglandin E2 levels in calves undergoing dehorning

The purpose of this study was to investigate the pharmacokinetics of intravenous flunixin (2.2 mg/kg b.w.), oral meloxicam (1mg/kg b.w.), oral gabapentin (15 mg/kg b.w.) alone or co-administrated with meloxicam as well as the effects of these compounds on prostaglandin E2 (PGE2) synthesis in calves subjected to surgical dehorning. Plasma samples collected up to 24h after drug administration were analyzed by liquid chromatography/mass spectrometry, whereas blood PGE2 levels were measured by immunoenzymatic assay. In plasma, the terminal half-live of flunixin, meloxicam and gabapentin were 6.0 h (range, 3.4-11.0 h), 16.7h (range, 13.7-21.3h) and 15.3h (range, 11-32.9h), respectively. The co-administration of single doses of gabapentin and meloxicam did not seem to affect the pharmacokinetic profile of the two drugs except for gabapentin that reached significantly (P<0.05) higher maximum serum concentration (Cmax) when co-administered with meloxicam, than when administered alone. At 5, 360 and 720 min after dehorning, a significant (P<0.01) decrease in PGE2 concentration was observed in flunixin-treated animals compared with control calves. Moreover, circulating log PGE2 concentrations were inversely proportional to log flunixin concentrations (R(2)=0.75; P<0.0001). None of the other drugs significantly affected blood PGE2 levels. Further assessment of oral meloxicam and gabapentin in established pain models is required to formulate science based analgesic recommendations to enhance animal well-being after dehorning.

Effects of housing and short-term transportation on hormone and lymphocyte receptor concentrations in beef cattle

The experiment was designed to evaluate the effects of housing system and short-term transportation on the pituitary and adrenal response and on blood progesterone concentrations of beef cattle. Since the use of steroid hormones in farm animals has been banned in the EU (Council Directive 96/22/EC), it seems important to study the possible modifications in serum progesterone concentrations induced by stress in cattle. Thirty-two, 6 months old male Piedmontese beef cattle (16 reared in a littered loose house, Group A, and 16 housed in a littered tying stall barn, Group B) were blood sampled at T1 (6 months old), T2 (12 months old), T3 (18 months old, before transportation to the slaughterhouse) and T4 (after transportation to the slaughterhouse) in order to measure hormonal concentrations and lymphocyte glucocorticoid (GR) and β-adrenergic (β-AR) receptor concentrations. Circulating hormone concentrations were measured using commercial radioimmunoassay kits, whereas lymphocyte receptor density was determined through binding assays. In beef cattle housed in tie stall barn a significant increase in serum cortisol concentration was observed at T3, whereas there was no effect of the housing system on blood progesterone concentrations. Short-term transportation caused a significant increase in blood cortisol and catecholamine concentrations in both groups, whereas lymphocyte GR and β-AR significantly decreased in Group A. Our data confirm the activation of the hypothalamic-pituitary-adrenal axis and the catecholaminergic system in short-term transportation and suggest that the stress-induced increase in circulating progesterone concentrations does not exceed the limit established by pending legislation.

Expression and functionality of TRPV1 receptor in human MCF-7 and canine CF.41 cells

As canine mammary tumours (CMT) and human breast cancer share clinical and prognostic features, the former have been proposed as a model to study carcinogenesis and improved therapeutic treatment in human breast cancer. In recent years, it has been shown that transient receptor potential vanilloid 1 (TRPV1) is expressed in different neoplastic tissues and its activation has been associated with regulation of cancer growth and progression. The aim of the present research was to demonstrate the presence of TRPV1 in human and canine mammary cancer cells, MCF-7 and CF.41, respectively, and to study the role of TRPV1 in regulating cell proliferation. The images obtained by Western blot showed a signal at 100 kDa corresponding to the molecular weight of TRPV1 receptor. All tested TRPV1 agonists and antagonists caused a significant decrease (P < 0.05) of cell growth rate in MCF-7 cells. By contrast, in CF.41 cells capsaicin and capsazepine induced a significant increase (P < 0.05) in cell proliferation, whereas resiniferatoxin (RTX) and 5-iodo-resiniferatoxin (5-I-RTX) had no influence on CF.41 cell proliferation. Further studies are needed to elucidate the underlying molecular mechanism responsible for the different effects evoked by TRPV1 activation in MCF-7 and CF.41 cells.

Identification of Functional α-Adrenoceptor Subtypes in the Bovine Female Genital Tract During Different Phases of the Oestrous Cycle

The concentration and functionality of the α-adrenoceptor (α-AR) subtypes in the genital tract of cyclic heifers were investigated. In each tissue sample, a single class of α1-ARs was observed, whereas two distinct classes of α2-ARs were discriminated: low-affinity (LA) and high-affinity (HA) α2-ARs. Statistical analysis showed the presence of significantly (p < 0.05) higher concentrations of all α-AR subtypes in the follicle than in the corpus luteum. No significant differences were found in the ovary or myometrium between the luteal and follicular phases. In the ovary, the density of α1-ARs was significantly (p < 0.05) higher than that of α2-ARs. By contrast, there were significantly (p < 0.05) more α2-ARs than α1-ARs in the myometrium. As far as α2-ARs are concerned, LA α2-ARs were significantly (p < 0.05) higher than HA α2-ARs in all tested tissues. Competition studies suggested that the rank order of potency of antagonists for α1-ARs was prazosin > phentolamine > yohimbine, whereas for α2-ARs the order of potency was yohimbine ≥ phentolamine > prazosin. Functional assays performed on myometrium showed that noradrenaline, phenylephrine and clonidine elicited concentration-dependent contractions only in dioestrus and pro-oestrus preparations and that clonidine was more effective than phenylephrine as a contractile agent. It appeared that there were no significant modifications in α-AR affinity or concentration during the different stages of bovine oestrous cycle, whereas the uterine spontaneous activity and the responsiveness to α-adrenergic stimulation was strongly influenced by hormonal levels. The modifications of uterine contractility observed during the oestrous cycle may be related to modifications induced in the transductional mechanisms of α-ARs.

Pharmacological treatments and risks for the food chain

Veterinarians play a pivotal role in public health control, in particular in the management of risks deriving from pharmacological treatments of food-producing animals. Veterinary medicinal products can represent a risk for animal health and welfare (side effects, decreased efficacy), for farmers and practitioners administering the drug, for consumers of food of animal origin (presence of residues, occurrence of antibiotic resistance) and for the environment. According to pending European guidelines, risk management starts from marketing authorisation that must be based on risk evaluation and can be denied when the risk/benefit ratio is not favourable considering the advantages for animal health and welfare and for safety of consumers. Veterinarians can prevent and control risks by using correct pharmacological criteria to choose and administer medicinal products and undertaking risk-based inspection of residues of drugs in food of animal origin. Moreover, a major tool for veterinarians to prevent and control drug-borne risk is “pharmacovigilance”. Risks for the environment are usually assessed during the pre-marketing approval process, however veterinarians, as risk managers, should educate farmers about correct drug handling and disposal, and periodically verify that suggested measures are applied.

In vitro and ex vivo pharmacodynamics of selected non-steroidal anti-inflammatory drugs in equine whole blood.

Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit cyclooxygenases (COX), and the inhibition of COX-2 rather than COX-1 can limit the onset of NSAID-related adverse effects. The pharmacodynamic properties of eltenac, naproxen, tepoxalin, SC-560 and NS 398 in healthy horses were investigated using an in vitro whole blood assay. To predict COX selectivity in clinical use, eltenac and naproxen were also studied ex vivo after intravenous administration. SC-560 acted as a selective COX-1 inhibitor, tepoxalin as a dual inhibitor with potent activity against COX-1, and NS 398 as a preferential COX-2 inhibitor. Eltenac was a preferential COX-2 inhibitor in vitro but un-selective in the ex vivo study. Naproxen maintained its non-selectivity both in vitro and ex vivo. These findings have demonstrated that in vitro studies may not accurately predict in vivo NSAID selectivity for COX and should be confirmed using an ex vivo whole blood assay.

Effects induced by exercise on lymphocyte β-adrenergic receptors and plasma catecholamine levels in performance horses.

The effect of dynamic exercise on complete blood cell count, lymphocyte β-adrenergic receptor and plasma catecholamine (adrenaline and noradrenaline) levels in horses performing different disciplines were investigated during rest and after exercise. Blood samples were collected from jumping horses (n=6), Arabian Endurance horses (n=6) and Standardbred trotters (n=6) before and immediately after competition. Dynamic exercise caused a significant increase in red blood cell count (Standardbred trotters: P=0.0012), haemoglobin concentration (jumping horses: P=0.001; Standardbred trotters: P=0.01), haematocrit percentage (Standardbred trotters: P=0.005), neutrophil percentage (jumping horses: P=0.0003), lymphocyte percentage (jumping horses: P=0.0003), monocyte percentage (Standardbred trotters: P=0.0008), lymphocyte β-AR numbers (jumping horses: P=0.01; Arabian Endurance horses: P=0.016; Standardbred trotters: P=0.05), plasma adrenaline concentration (Standardbred trotters: P=0.0001) and plasma noradrenaline levels (Standardbred trotters: P=0.003). It is concluded that acute increases in plasma catecholamine concentrations depended on the exercise performed and may induce up-regulation of β-AR in equine lymphocytes. However, the exact mechanism of β-AR up-regulation still remains unclear.

Genetic and phenotypic characterisation of Escherichia coli producing cefotaximase-type extended-spectrum β-lactamases: first evidence of the ST131 clone in cats with urinary infections in Italy

The incidence of cefotaximase (CTX-M)-type extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has increased dramatically in humans and animals since the middle of the last century. E coli that produce CTX-M β-lactamase represent a major cause of urinary tract infections, and pose a significant therapeutic challenge to both human and veterinary medicine. As data on uropathogenic CTX-M-producing strains in cats are limited, the aim of this study was to describe the genetic character and antibiotic resistance phenotypes of CTX-M-producing E coli isolated from cats with cystitis. Seven of 15 E coli bacteria isolated from 138 urine samples had the CTX-M gene and were therefore included in this study. These isolates were screened by polymerase chain reaction for the presence of 14 extra-intestinal virulence factors, class 1 and class 2 integrons, and to identify their phylogenetic groups. Multi-locus sequence typing (MLST) of the strains and susceptibility testing (disc diffusion method) were also performed. Virulence factor iutA was the most frequent determinant identified (86.7%), and the majority of CTX-M-producing strains (n = 5) carried class 1 integrons. MLST allowed us to discriminate four known sequence types (ST131, ST555, ST602, ST155) and three novel sequence types (ST3847, ST3848, ST4181). To the best of our knowledge, this is the first study to report uropathogenic CTX-M-producing E coli ST131 in cats in Italy. Accurate diagnostics and prudent use of antimicrobials are recommended to avoid the spread of multidrug-resistant pathogens in veterinary medicine and to prevent their transmission to humans.

Identification of functional β-adrenoceptors in Caco-2 cell membranes

R. Odore1*, P. Badino1, A.L. Stammati2, I. De Angelis2, F. Zucco3, C. Belloli4 and G. Re1 1Department of Animal Pathology, Division of Veterinary Pharmacology and T oxicology, University of T orino, Grugliasco (T o); 2L aboratory of Compared T oxicology and Ecotoxicology, Istituto Superiore di Sanità, Rome; 3Institute of Biomedical T echnologies, CNR, Rome; 4Department of Animal Health and Welfare, Division of Pharmacology and T oxicology, University of Bari, Valenzano (Ba), Italy *Correspondence: Department of Animal Pathology, Division of Veterinary Pharmacology and T oxicology, University of T orino, V ia L eonardo da V inci 44, 10095 Grugliasco (T o), Italy E-mail: odore@veter.unito.it