Preliminary comparative serological evaluation of Histamine H2 receptors in dogs with an acute onset of vomiting treated with Ranitidine and healthy dogs

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Ranitidine (RT) is an antagonist against H2 histamine receptors (H2R) that weakly suppress acid secretion in patients. Despite that a clinical effect is often achieved.

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H2 antagonists (H2RA) also called H2 blockers, are a group of medications that block the action of histamine at the H2R of parietal cells in the stomach.

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Preliminary analysis indicates that the levels of H2 receptors in the serum and gastric walls are the same.

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Evidence suggests that the level of H2 receptors in dogs with acute vomiting is greater than in healthy dogs, thus probably contributing to a greater efficiency of ranitidine treatment.

Despite the lack of evidence of the ability to suppress gastric acid secretion in dogs, ranitidine (RT) is often used to control clinical signs in dogs with acute vomiting even if the way it happens it is still largely unknown. The aim of this study was thus to evaluate the therapeutic effect of ranitidine on H2 receptors in dogs with acute vomiting. To investigate the RT activity a preliminary study was performed in dogs which underwent gastroscopy analyses, demonstrating that the level of H2R observed in the serum and gastric wall tissue was the same [1.473(1.30; 1.79) ng/ml and 1.498 (1.33; 1.85) ng/ml, respectively]. After that H2R levels in the serum of 22 healthy dogs (Group 1) and in a group of 22 dogs with acute vomiting (Group 2) were compared both before (T0), after 7–10 days (T1) of 2 mg/kg twice a day ranitidine administration and after 11 days since the drug was discontinued (T2). Significant differences (p<0.001) were detected between the level of circulating H2R among Group 1: 0.41 ng/ml (0.28;0.54) and Group 2: 2.27 ng/ml (2.11;2.49) at T0. In Group 2, no difference in the level of H2R was detected in samples collected at T0 compared to those at T1 [T1: 2.32 ng/ml (2.14; 2.49)] and T2 [T2: 2.30 ng/ml (1.99;2.69)]. In Group 2 all patients but one displayed remission of symptoms attributable to inflammatory gastropathy at the first withdrawal (T1: 7–10 days), while at the second withdrawal (T2: after 21 days), remission was detected in all dogs. Our preliminary hypothesis is that the clinical efficacy of ranitidine is related to the greater expression of H2 receptors in patients with acute vomiting. This increased expression may be due to continuous pathological stimulus at the gastric level. Further studies with a wider population are needed to better investigate the activity of RT in dogs with acute onset of vomiting.

Different distribution of antimicrobial resistance genes and virulence profiles of Staphylococcus aureus strains isolated from clinical mastitis in six countries

Staphylococcus aureus is recognized worldwide as one of the main contagious mastitis agents in cattle and can express a set of antimicrobial resistance genes and virulence-associated genes that explain the wide range of outcomes of intramammary infections. Staphylococcus aureus strains are heterogeneous: their different resistance and virulence patterns, associated with host-level factors and treatment factors, are related to the severity of infection. The aim of this study was to determine phenotypic antibiotic susceptibility, occurrence of selected antimicrobial resistance genes and other virulence genes in 93 S. aureus strains isolated from clinical mastitis in 6 countries: Argentina, Brazil, Germany, Italy, the United States (New York State), and South Africa. These isolates were tested against a total of 16 drugs (amoxicillin-clavulanate, ampicillin, cefazolin, cefoperazone, cefquinome, enrofloxacin, erythromycin, gentamicin, kanamycin, lincomycin, oxacillin, penicillin, rifampin, spiramycin, sulfamethoxazole/trimethoprim, tylosin) by minimum inhibitory concentration (MIC) assay, and examined for the presence of 6 antibiotic-resistance genes (blaZ, mecA, mecC, ermA, ermB, ermC) and 6 virulence-associated genes (scn, chp, sak, hla, hlb, sea) via PCR analysis. The phenotypic results of this study revealed the presence of 19.4% penicillin-resistant strains, whereas 22.6% of the strains were classified as having resistance (5.4%) or intermediate resistance (17.2%) to erythromycin. Most (96.8%) of the isolates were inhibited by cephalosporins, and all were susceptible to amoxicillin-clavulanate. Two strains (1 from Germany, 1 from Italy) were resistant to oxacillin and were positive for mecA. Among the other antimicrobial resistance genes, the most frequently detected was blaZ (46.2%), and 32.3% of the isolates were positive for erm genes: ermC (21.5%) and ermB (10.8%). The most prevalent virulence gene was hla (100%), followed by hlb (84.9%) and sea (65.6%). These results show a low prevalence of antibiotic multidrug resistance in S. aureus isolates, even if the detection of selected antimicrobial resistance genes did not always correspond with the occurrence of phenotypic antibiotic resistance; the immune evasion cluster gene prevalence was quite low in the samples analyzed.

Pharmacokinetic and pharmacodynamic evaluations of a 10 mg/kg enrofloxacin intramuscular administration in bearded dragons (Pogona vitticeps): a preliminary assessment

Enrofloxacin (E) is commonly used in veterinary medicine. It is necessary to perform pharmacokinetic/dynamic studies to minimize the selection of resistant mutants of bacteria and extend the efficacy of antimicrobial agents. Eight healthy adult Pogona vitticeps were assigned into two groups of equal size and treated with a single intramuscular injection of E at 10 mg/kg. Blood samples were withdrawn at different scheduled times for each group, and rectal swabs were collected. E and ciprofloxacin (active metabolite) blood concentrations were quantified by an HPLC validated method, while the in vitro antimicrobial susceptibility was evaluated by the Kirby-Bauer disc diffusion susceptibility test. The pharmacokinetic profiles of E gave similar pharmacokinetic parameters irrespective of the collection time schedule. Bacteria isolation showed the presence of both E. coli, Salmonella enterica subspecies enterica and subspecies 3a, Proteus spp., and Pseudomonas spp. The majority of isolated colonies were sensitive to E, but the treatment did not reduce the number of bacteria in faeces. Results suggest that E is able to reach blood concentrations high enough to kill susceptible bacteria (MIC < 0.9 μg/mL), but at the same time does not significantly affect intestinal bacteria.

The pharmacokinetics and in vitro/ex vivo cyclooxygenase selectivity of parecoxib and its active metabolite valdecoxib in cats

Parecoxib (PX) is an injectable prodrug of valdecoxib (VX, which is a selective cyclo-oxyganase-2 (COX-2)) inhibitor licensed for humans. The aim of the present study was to evaluate pharmacokinetics and in vitro/ex vivo cyclooxygenase selectivity of PX and VX in cats. In a whole blood in vitro study, PX did not affect either COX enzymes whereas VX revealed a COX-2 selective inhibitory effect in feline whole blood. The IC50 values of VX for COX-2 and COX-1 were 0.45 and 38.6 µM, respectively. Six male cats were treated with 2.5 mg/kg of PX by intramuscular injection. PX was rapidly converted to VX with a relatively short half-life of 0.4 h. VX achieved peak plasma concentration (2.79 ± 1.59 µg/mL) at 7 h following PX injection. The mean residence times for PX and VX were 0.43 ± 0.15 and 5.94 ± 0.88 h, respectively. In the ex vivo study, PX showed a COX-2 inhibition rate of about 70% in samples taken at 1, 2, 4 and 10 h after injection, with a significant difference compared to the control. In contrast, COX-1 was slightly inhibited, ranging from 0.7% to 9.7% of the control inhibition rate without any significant difference for 24 h after PX administration. The preliminary findings of the present research appear promising and encourage further studies to investigate whether PX can be successfully used in feline medicine.

Fire-eater's pneumonia: a likely hazard not uncommon in fire eaters

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Effects of flunixin meglumine and ketoprofen on mediator production in ex vivo and in vitro models of inflammation in healthy dairy cows

In this study, ex vivo assays were carried out in dairy cows to evaluate the anti-inflammatory effects of two nonsteroidal anti-inflammatory drugs: ketoprofen (KETO) and flunixin meglumine (FM). Twelve healthy Holstein dairy cattle were randomly allocated to two groups (n=6): group 1 received FM and group 2 received KETO at recommended therapeutic dosages. The anti-inflammatory effects of both drugs were determined by measuring the production of coagulation-induced thromboxane B2 (TXB2 ), lipopolysaccharides (LPS) (10 μg/mL)-induced prostaglandin E2 (PGE2 ), and calcium ionophore (60 μm)-induced leukotrien B4 (LTB4 ). Cytokine production was assessed by measuring tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and interleukin-8 (CXCL8) concentrations after incubation in the presence of 10 μg/mL LPS. The IC50 of FM and KETO was determined in vitro by determining the concentration of TXB2 and PGE2 in the presence of scalar drug concentrations (10(-9) -10(-3) m). Both FM and KETO inhibited the two COX isoforms in vitro, but showed a preference for COX-1. FM and KETO showed similar anti-inflammatory effects in the cow.

Palmitoylethanolamide, endocannabinoids and related cannabimimetic compounds in protection against tissue inflammation and pain: Potential use in companion animals

Endocannabinoids have analgesic/anti-inflammatory properties. The biology of endocannabinoids, their receptors, signalling mechanisms and role in the regulation of physiological processes have been extensively reviewed. This review focuses on the role of palmitoylethanolamide (PEA), an endogenous fatty acid amide analogue of the endocannabinoid anandamide, in tissue protective mechanisms. PEA was first identified almost five decades ago in lipid extracts of various natural products, and its anti-inflammatory and antinociceptive effects were established later. Evidence exists that PEA is synthesised during inflammation and tissue damage and a number of beneficial effects, including the relief of inflammation and pruritus, have been shown to be useful in the control of neurogenic and neuropathic pain. The postulated hypotheses as to the mode of action of PEA include a possible local autacoid-like mediator activity regulating mast-cell activity and putative activation of cannabinoids and vanilloid TRPV1 receptors via "entourage" effects. The large number of scientific investigations into the effects of PEA and PEA-related compounds has given rise to new therapeutic opportunities. In spite of the multitude of therapies currently employed to control inflammation, pain, pruritus and tissue damage, the possibility of using a natural compound, such as PEA to manipulate endogenous protective mechanisms may be considered a beneficial novel therapeutic strategy in veterinary medicine.

Intracranial Haemorrhage in Patients on Antithrombotics: Clinical Presentation and Determinants of Outcome in a Prospective Multicentric Study in Italian Emergency Departments

BACKGROUND

Intracranial haemorrhage (ICH) is the type of stroke associated with the highest death rate, and about 30% of ICH occurs in patients on antithrombotic treatment. This study relates clinical presentations and outcome of ICH patients on oral anticoagulant (OA) or antiplatelet (AP) therapy admitted to 33 Italian emergency departments (ED).

METHODS

Consecutive patients were enrolled after cranial computed tomography (CT). Primary outcome was the Modified Rankin Scale (MRS) score at 3 months of follow-up. Common descriptive statistics were computed after stratification for traumatic or spontaneous ICH and identification of the anatomical location of bleeding. Multivariate logistic regression was used to assess predictors of death.

RESULTS

We recruited 434 patients on AP therapy and 232 on OA. There were 432 spontaneous and 234 traumatic ICH patients. The proportions of AP and OA patients undergoing neurosurgery were 21.8 and 19.4%, respectively, while < 30% underwent procoagulant medical treatment. At the 3-month follow-up, the case fatality rate was 42.0%, while disability or death (MRS 3-6) was 68.1%. The odds ratio for death in OA versus AP patients was 2.63 (95% CI 1.73-4.00) in the whole population and 2.80 (95% CI 1.77-4.41) in intraparenchymal event patients. Glasgow Coma Scale, age, spontaneous event and anticoagulant use were found to be predictors of death both in traumatic and spontaneous events.

CONCLUSION

This study confirms the high prevalence of death or disability in OA and AP patients with ICH. As far as the determinants of mortality and disability are concerned, the results of this study might be useful in the clinical management and allocation of resources in the ED setting. The observed low use of procoagulant therapy highlights the need for ED educational programmes to heighten the awareness of available and effective haemostatic treatments.

Mepartricin long-term administration regulates steroid hormone and adrenergic receptor concentrations in the prostate of aged rats

Mepartricin is a semi-synthetic macrolide antibiotic developed as a drug for the treatment of benign prostatic hyperplasia (BPH) in human patients. In the present study, aged rats are used as an experimental model to evaluate the effects of mepartricin on circulating hormone concentrations and prostate receptor concentrations, to compare these possible effects with clinical findings observed in long-term treated dogs. Fifty-six aged male rats were randomly divided into four experimental groups treated orally with 0 (group 1), 2 mg (group 2), 5 mg (group 3) and 20 mg (group 4) mepartricin/kg of body weight. for 28 days respectively. Serum oestradiol and testosterone concentrations were measured by radio-immune-assays methods. Binding assays were used to measure the prostate concentrations of oestrogen receptors (ER), androgen receptors (AnR), alpha(1)-adrenergic receptor (alpha(1)-AR), and beta-adrenerergic receptor (beta-AR) subtypes. Mepartricin induced a significant reduction of prostate weight and serum oestradiol concentrations. Serum testosterone concentrations were unaffected. The treatment induced a significant down-regulation of ER concentrations (P < 0.05) and a significant up-regulation of AnR (P < 0.05) in rat prostate. Mepartricin induced a significant (P < 0.05) dose-dependent up-regulation of alpha(1)-AR and beta(2)-AR. In contrast, the concentration of beta(3)-ARs was significantly decreased (P < 0.05) in treated animals. The increase in prostate beta(2)-AR concentrations observed in subjects treated with mepartricin may be a favourable element in the evolution of BPH, because of the role exerted by these receptors in the control of prostatic smooth muscle relaxation. Curiously, beta(3)-AR concentrations were significantly reduced in treated animals. Data collected suggest that the prostatic beta-AR expression might be strongly influenced by oestrogen deprivation (mepartricin treatment); therefore, the combination of oestrogen suppression (mepartricin) and adrenergic suppression (alpha(1)-AR blockers) may be proposed as a possible nonhormonal therapeutic strategy for the treatment of benign prostatic hyperplasia in dogs.

Changes in lymphocyte glucocorticoid and beta-adrenergic receptors in veal calves treated with clenbuterol and steroid hormones for growth-promoting purposes*

In order to identify possible peripheral markers of illegal treatments with growth-promoting agents in veal calves, beta-adrenergic receptor (beta-AR) and glucocorticoid receptor (GR) concentrations were measured in lymphocytes of 12 male Friesian crossbred calves (six controls and six treated). The animals received a cocktail of anabolic and re-partitioning agents [17beta-oestradiol: 3 x 10 mg intramuscular (i.m.) doses at 17-day intervals; dexamethasone sodium phosphate: 4 mg/day for 6 days and 5 mg/day for six further days dissolved in milk; and clenbuterol: 20 microg/kg/day dissolved in milk for the last 40 days before slaughter]. Blood samples were collected by venipuncture at different time points and lymphocytes were isolated by density gradient centrifugation. Lymphocyte beta-AR and GR levels were measured by binding assays. Treatment with re-partitioning agents caused a significant down-regulation of lymphocyte beta-ARs 19 days after the beginning of clenbuterol administration and at day 55 (after dexamethasone withdrawal, just before slaughter). This phenomenon was partially reversed at day 50, after dexamethasone administration, at which time a significant decrease in GR concentrations also occurred. For both types of receptors, no significant changes in the dissociation constant values were observed at any time point. Lymphocytes express measurable concentrations of beta-ARs and GRs and the measurement of receptor levels highlights the fluctuation of receptor expression due to the dynamic interaction of the drugs used in combination. Lymphocyte receptor determination could therefore be included in a battery of biological assays to detect illegal treatments with anabolic agents in veal calves in the light of a multivariate approach.

Are so many adrenergic receptor subtypes really present in domestic animal tissues? A pharmacological perspective

Adrenergic receptors (ARs) are the cellular membrane binding sites through which natural catecholamines and sympathomimetic drugs exert their physiological and pharmacological effects. In recent decades, studies to clarify the distribution and function of ARs have been performed mostly on cultured cells, laboratory animals and human target tissues, but little is known about these aspects in domestic animals. This review focuses on AR structure, classification and signalling pathways and on AR subtype distribution in target tissues of some domestic animals, namely dogs, horses and bovines. In these species, different alpha- and beta-AR subtypes have been characterized and the functions controlled by the adrenergic systems have been studied. In the dog, the role played by the adrenergic system in the pathogenesis of cardiovascular disorders and in the modulation of canine aggression has roused particular interest. In dogs affected by dilated cardiomyopathy a significant down-regulation of beta-ARs has been observed both in the heart and circulating lymphocytes. This finding confirms the involvement of the adrenergic system in the pathogenesis and progression of the disorder and suggests new therapeutic strategies. In the horse, AR distribution has been studied in the cardiac, respiratory and gastrointestinal systems as well as in digital veins and arteries. The cardiac beta-ARs in healthy horses seem to be predominantly represented by the beta(1) subtype. In this species, heart failure may increase the expression of the beta(2) subtype, rather than causing AR down-regulation. Different beta- and alpha-AR subtypes have been characterized in the smooth muscle of equine ileum. The sympathetic relaxation of equine ileum smooth muscle seems to depend mainly on beta(3)-AR subtype activation, with minor involvement of the beta(2) subtype. In the respiratory tract, regional differences have been evidenced in the functionality of beta-AR subtype. The beta(2) subtype predominates in all segments but the beta(2) subtype-mediated adenyl cyclase response is tissue-dependent, with higher activity in tracheal membranes than bronchial or pulmonary ones. Both alpha- and beta-AR subtypes are present in the genital tract of cows. Bovine ovarian and myometrial cell membranes express higher concentrations of beta(2)-ARs than the beta(1) subtype, whereas as far as alpha-ARs are concerned, a single class of alpha(1)-ARs and two distinct classes of alpha(2)-AR binding sites have been discriminated. Interestingly, it has been observed that the activation of the sympathetic system could play an important role in the pathogenesis of bovine ovarian cysts as suggested by the modifications in beta-AR levels in the hypophysis and ovary of cows affected by ovarian cysts. In this species, the phenomenon of down-regulation has been well studied in different organs of veal calves treated with clenbuterol as a "partitioning agent". Since differences exist in AR distribution among species, data obtained in laboratory animals or in human beings cannot be extrapolated to domestic animals and further investigation on AR subtypes in domestic animal tissues is necessary.

Road transportation affects blood hormone levels and lymphocyte glucocorticoid and β-adrenergic receptor concentrations in calves

The effect of transportation on blood cortisol and catecholamine levels, lymphocyte glucocorticoid receptor (GR) and beta-adrenergic receptor (beta-AR) concentrations was investigated in calves. Blood samples were collected from 24 six-month-old calves before departure (T(0)), on arrival (T(1)), and at 24 h (T(2)) and one week (T(3)) after arrival. Animals were loaded and transported about 950 km, from the Midy-Pyrenes region (Cahors, France) to the Piedmont region (Italy), over a total of 14 h. Serum cortisol levels and plasma catecholamines (adrenaline, noradrenaline) were determined by radioimmunoassay. Lymphocyte GRs and beta-ARs were measured through binding assays. A significant (P < 0.05) increase in cortisol and catecholamine concentrations was observed immediately after transport. The increase in hormone levels at time T(1) was negatively correlated with lymphocyte GR and beta-AR concentrations. At times T(2) and T(3), blood cortisol and catecholamine levels and lymphocyte GRs and beta-ARs returned to normal. The results demonstrate the activation of the hypothalamic-pituitary-adrenal axis and the catecholaminergic system in long-term transported calves. However, these systems returned to normal within 24 h after the end of transport.

Adrenergic regulation of vascular smooth muscle tone in calf digital artery

Radioligand binding studies and functional assays on isolated smooth muscle preparations were performed in order to obtain a biochemical and functional characterization of the beta-adrenoceptor (beta-AR) subtypes involved in regulation of the smooth muscle relaxation of the calf's common digital artery. The results indicate that the common digital artery possesses two beta-AR populations (40% beta(1) and 60% beta(2)) and the beta(2)-subtype appears to predominate as far as function is concerned. Only the beta(2)-AR agonists clenbuterol and fenoterol caused dose-related relaxant effects, antagonized by propranolol, when tested in preparations precontracted both with PGF(2alpha) (1.4 x 10(-5) m) and noradrenaline (1.2 x 10(-6) m). In noradrenaline precontracted preparations the beta(1)-AR selective agonists dobutamine and xamoterol caused vasodilation which was not antagonized by (+/-)propranolol. While the functional relaxant effects of dobutamine may be attributed to its potent competitive alpha-AR blocking activity, further investigations are required to explain the effect of xamoterol. The vasodilator effect of (+/-)isoproterenol was irregular. The recorded contractile effects, mainly at dosages greater than 10(-6) m, suggest the loss of drug selectivity for beta-AR and alpha-AR activation. Indirect evidence indicates that the alpha-adrenoceptor (alpha-AR) population in this tissue which produces a strong contraction is functionally dominant over the beta-AR, suggesting limited therapeutic benefit for beta-AR drugs to control blood flow disorders in the calf's distal limb.

Identification of functional alpha-adrenoceptor subtypes in the bovine female genital tract during different phases of the oestrous cycle

The concentration and functionality of the alpha-adrenoceptor (alpha-AR) subtypes in the genital tract of cyclic heifers were investigated. In each tissue sample, a single class of alpha1-ARs was observed, whereas two distinct classes of alpha2-ARs were discriminated: low-affinity (LA) and high-affinity (HA) alpha2-ARs. Statistical analysis showed the presence of significantly (p < 0.05) higher concentrations of all alpha-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 alpha1-ARs was significantly (p < 0.05) higher than that of alpha2-ARs. By contrast, there were significantly (p < 0.05) more alpha2-ARs than alpha1-ARs in the myometrium. As far as alpha2-ARs are concerned, LA alpha2-ARs were significantly (p<0.05) higher than HA alpha2-ARs in all tested tissues. Competition studies suggested that the rank order of potency of antagonists for alpha1-ARs was prazosin > phentolamine > yohimbine, whereas for alpha2-ARs the order of potency was yohimbine > or = 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 alpha-AR affinity or concentration during the different stages of bovine oestrous cycle, whereas the uterine spontaneous activity and the responsiveness to alpha-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 alpha-ARs.

Characterization of alpha-adrenoceptor subtypes in smooth muscle of equine ileum

OBJECTIVE

To determine the concentration and binding characteristics of alpha-adrenoceptor subtypes in smooth muscle cell membranes of equine ileum.

SAMPLE POPULATION

Segments of longitudinal and circular smooth muscle from the ileum of 8 male and 8 female adult horses.

PROCEDURE

Distribution of alpha-adrenoceptor subtypes was assessed by use of radioligand binding assays incorporating [3H]-prazosin and [3H]-rauwolscine, highly selective alpha1- and alpha2-adrenoceptor antagonists, respectively. Characterization of adrenoceptor subtypes was performed by use of binding inhibition assays.

RESULTS

On the basis of binding affinity for specific radioligands, low- and high-affinity alpha1- and alpha2-adrenoceptors were detected. Concentration of low-affinity alpha2-adrenoceptors was significantly greater in male horses, compared with females. Competition studies confirmed the specificity of the radioligands used in the binding assays. Alpha1-adrenoceptors of both subtypes in male and female horses had a higher affinity for prazosin than phentolamine, whereas yohimbine did not compete with the radioligand for binding. For alpha2-adrenoceptors regardless of subtype, potency of inhibition elicited by each drug varied between sexes. In males, yohimbine was a more potent inhibitor than phentolamine, which was more potent than prazosin. In females, yohimbine was more potent than prazosin, which was more potent than phentolamine.

CONCLUSIONS AND CLINICAL RELEVANCE

High- and low-affinity alpha1- and alpha2-adrenoceptors were detected in smooth muscle of equine ileum. Because alpha-adrenoceptor subtypes, particularly alpha2-adrenoceptors, are involved in the regulation of gastrointestinal tract function, characterization of these receptors may represent the basis for development of new therapeutic strategies for the control of gastrointestinal disturbances in horses.

Identification and coupling to adenylate cyclase of three different [(3)H]CGP 12177 binding sites in Caco-2 cell membranes

In the present investigation the identification of beta -adrenoceptor (beta -ARs) subtypes in the Caco-2 cell line was performed using radiometric assays. beta -ARs were measured using increasing concentrations of the highly specific beta -AR antagonist (-)[(3)H]CGP 12177 (0.06-4 nM), whereas the beta(1)- and beta(2)-AR subtypes discriminated through selective binding assays using the highly selective unlabelled antagonists CGP 20712A and ICI 118551. Atypical beta -ARs were measured using an incubation system formed by higher concentrations (0.6-20 nM) of (-)[(3)H]CGP 12177. beta - Atypical binding site concentrations (69 +/- 5 fmol mg ml(-1)of membrane protein) were higher than beta(1)-ARs (7 +/- 1) and beta(2)-ARs (24 +/- 2), respectively. The different beta -AR subtype affinities were characterized by binding inhibition experiments and the adrenergic agonists displaced the radioligand from its specific binding sites in the following order of potency: isoproterenol > clenbuterol > dobutamine > SR 58611A; for antagonists the order of potency was: propranolol approximately = ICI118551 approximately = CGP20712A. For atypical beta -ARs the order was: SR 58611A > clenbuterol > dobutamine > isoproterenol for agonists and propranolol > CGP 20712A > ICI 118551 for antagonists. As far as in vitro functional studies are concerned, beta -AR subtypes were shown to be coupled to adenylyl cyclase as their stimulation produced cAMP in an amount significantly higher than basal values. cAMP production after stimulation with dobutamine, clenbuterol, isoproterenol, and SR 58611A was measured using a cAMP radioassay kit. The order of efficacy suggested that the stimulation of beta(2)-ARs was the most effective in inducing the activation of cell signalling mechanisms. The identification of functional beta -ARs in a cancer cell line represents the first step in the study of the possible adrenergic control of cellular activities (e.g. proliferation and/or differentiation), which could suggest the use of this cancer cell line as a model for the study of cell activity or possibly new therapeutic strategies.

Effects of mepartricin on estradiol and testosterone serum levels and on prostatic estrogen, androgen and adrenergic receptor concentrations in adult rats

The effects induced by oral administration of 0, 5 and 20 mg of meparticin kg(-1)of body weight for 28 days (group 1, 2 and 3, respectively) upon prostatic estrogen, androgen, alpha(1)- and beta-adrenergic receptor concentrations and on estradiol and testosterone serum levels in adult male rats were studied. The effects produced by mepartricin treatments on the weight and dimension of the gland were investigated. Both mepartricin dosages induced significant decreases (P< 0.05) of the absolute and relative weights and of the dimensions of the prostate. A significant dose-dependent decrease (P< 0.05) in estradiol serum levels was observed in treated rats, whereas no significant modifications were found in testosterone serum levels. As far as prostatic steroid receptor concentrations were concerned, a significant (P< 0.05) decrease in estrogen receptor number was observed in both treated groups, whilst a significant increase (P< 0.05) of androgen receptor concentrations was recorded only in rats treated with 20 mg mepartricin kg(-1). Conversely, a dose-dependent up-regulation of both prostatic alpha(1)- and beta-AR was found. Data obtained suggest that the prostatic alpha(1)-AR expression may be strongly influenced by estrogen deprivation (mepartricin treatment), therefore the combination of estrogen suppression (mepartricin) and adrenergic suppression (alpha(1)-AR blockers) may be suggested as a possible pharmacotherapeutic strategy for the treatment of benign prostatic hyperplasia.

PTX3, A prototypical long pentraxin, is an early indicator of acute myocardial infarction in humans

BACKGROUND

Inflammation is an important component of ischemic heart disease. PTX3 is a long pentraxin whose expression is induced by cytokines in endothelial cells, mononuclear phagocytes, and myocardium. The possibility that PTX3 is altered in patients with acute myocardial infarction (AMI) has not yet been tested.

METHODS AND RESULTS

Blood samples were collected from 37 patients admitted to the coronary care unit (CCU) with symptoms of AMI. PTX3 plasma concentrations, as measured by ELISA, higher than the mean+2 SD of age-matched controls (2.01 ng/mL) were found in 27 patients within the first 24 hours of CCU admission. PTX3 peaked at 7.5 hours after CCU admission, and mean peak concentration was 6.94+/-11.26 ng/mL. Plasma concentrations of PTX3 returned to normal in all but 3 patients at hospital discharge and were unrelated to AMI site or extent, Killip class at entry, hours from symptom onset, and thrombolysis. C-reactive protein peaked in plasma at 24 hours after CCU admission, much later than PTX3 (P<0.001). Patients >64 years old and women had significantly higher PTX3 concentrations at 24 hours (P<0.05). PTX3 was detected by immunohistochemistry in normal but not in necrotic myocytes.

CONCLUSIONS

PTX3 is present in the intact myocardium, increases in the blood of patients with AMI, and disappears from damaged myocytes. We suggest that PTX3 is an early indicator of myocyte irreversible injury in ischemic cardiomyopathy.

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 microg/ml, 12.5 microg/ml, 50 microg/ml and 6.25 microg/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.

Eye muscle paralysis after Vipera aspis envenomation

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Canine dilated cardiomyopathy: lymphocyte and cardiac alpha(1)- and beta-adrenoceptor concentrations in normal and affected great danes

Serum catecholamine levels and myocardial and lymphocyte adrenergic receptor (AR) concentrations were measured in adult great danes affected by canine dilated cardiomyopathy (DCM) and compared to those of healthy animals. A non-homogeneous population of beta -AR, consisting of beta(1)-AR and beta(2)-AR, was observed in healthy (41 and 59%, respectively) and affected (17 and 83%, respectively) dog lymphocytes. Binding assays revealed that total beta -AR, beta(1)-AR and alpha(1)-AR were significantly downregulated (P<0.05;P<0.01;P<0. 001), both in lymphocyte and myocardial cell membranes of affected dogs. beta(2)-Adrenergic receptor concentrations were significantly reduced only in lymphocyte and right atrium cell membranes (P<0.05). Downregulation was not associated with alterations in receptor binding characteristics, as no significant differences in K(d)values were found. Mean plasma catecholamine levels were significantly higher (P<0.01) in DCM dogs (939+/-41) than in normal subjects (348+/-32), thus suggesting a sympathetic activation. The present study indicates a condition similar to that observed in human patients affected by DCM and that adrenergic receptors in canine lymphocytes reflect the fluctuation of adrenergic receptor concentrations in the myocardium.

Lymphocyte beta -adrenoceptor downregulation in great danes with occult dilated cardiomyopathy (DCM) and with DCM and heart failure

The importance of the adrenergic nervous system in supporting the failing heart has long been known. The adrenergic drive on cardiac structure and function has however some adverse effects, which include myocardial beta-adrenoceptor (beta-AR) downregulation and decreased beta-adrenergic responsiveness to cathecolamines. In dog lymphocytes, beta(1)-AR and beta(2)-AR populations are almost equally represented (with a slight prevalence of beta(2)) and a significant correlation between cardiac and lymphocytic adrenoceptors has been found. The aim of the present study was to investigate possible differences between the concentration of lymphocytic beta-AR in healthy dogs, dogs with dilated cardiomyopathy (DCM) and dogs with occult DCM. Three groups of great danes were considered: a control group (n =10), dogs with DCM (n =9) and dogs with occult DCM (n =4). Lymphocytic beta-AR populations were determined in all dogs. A substantial and significant decrease (P<0.05) in total-AR, beta(1)-AR and beta(2)-AR concentrations in the lymphocytes of dogs with symptomatic DCM and occult DCM compared to the control group was found. Although the mean value of the lymphocyte beta(1)-AR number in the asymptomatic group was double compared to the DCM group, this difference was not statistically significant. We conclude that in dogs beta-AR downregulation occurs early in the course of dilated cardiomyopathy. This finding may suggest the value of early use of a beta-blocker in the therapeutic regimen. Moreover, the continuous monitoring of lymphocytic beta-AR may represent a useful tool for the development of a more effective individual therapy.

Investigations on the stereoselective action of isoxsuprine on alpha- and beta-adrenoceptors in equine common digital artery

The affinity and functional effects of isoxsuprine enantiomers were investigated to determine the enantiospecificity of the beta-agonistic and alpha-blocking effects. Functional assays on isolated smooth muscle preparations from equine common digital artery were performed to determine the apparent affinity (pD(2)) and intrinsic activity (alpha(E)) of (-)erythro-isoxsuprine (alphaS, betaR, gammaR) and (+)erythro-isoxsuprine (alphaR, betaS, gammaS). The affinity of two enantiomers for the different adrenoceptor types was studied by radioligand binding assays on membrane preparations from the same tissue, using (-)[(3)H]CGP12177 and [(3)H]prazosin. On noradrenaline-precontracted artery preparations (-)isoxsuprine was markedly more potent than (+)isoxsuprine in dilating preparations, indicating that the laevorotatory enantiomer has a very high apparent affinity for alpha-adrenoceptors. Binding studies confirmed that (-)isoxsuprine has a higher affinity than (+)isoxsuprine for alpha-adrenoceptors, while the (+) isomer competes for beta-adrenoceptors with an affinity similar to that of propranolol. As described for other beta-phenylethylamines, the two isoxsuprine enantiomers studied have different efficacies for alpha- and beta-adrenoceptors and the effects of the commercially available mixture of stereoisomers therefore depend on the density and functional importance of the adrenoceptor types present in the tissue studied. 1999 Academic Press.

Modifications of receptor concentrations for adrenaline, steroid hormones, prostaglandin F2alpha and gonadotropins in hypophysis and ovary of dairy cows with ovarian cysts

Receptor concentrations for adrenaline, steroid hormones, PGF2alpha, LH and FSH were measured in the hypophysis and ovary of dairy cows with ovarian cysts and the results were compared with those of healthy animals. Significant modifications were found in all receptor concentrations, either between follicular and luteal structures or between the hypophyseal and ovarian receptorial status. The correlations between catecholaminergic and steroidal systems have already been demonstrated, particularly those existing between beta-adrenoceptors and steroid hormone receptors. Particular attention has been given to the possibility that a derangement in neurogenic inputs may be at the basis of some ovarian pathologies. The results of the present study suggest that the modifications of the ovarian and hypophyseal receptorial status of healthy and affected cows could play an important role in the pathogenesis of ovarian cysts.

Serum pancreatic enzymes in patients with coma due to head injury or acute stroke

Serum amylase and lipase were measured in 32 patients with cerebral ischemia, 19 with spontaneous cerebral hemorrhage, 15 with head injury and intracranial bleeding, and 22 with head injury without intracranial bleeding; 20 healthy subjects were also studied as controls. Serum pancreatic isoamylase concentrations were assayed in hyperamylasemic sera. The overall incidence of hyperamylasemia was 14% (12 of 88 patients: 4 with cerebral ischemia, 4 with spontaneous cerebral hemorrhage, 1 with head injury and intracranial bleeding, and 3 with head injury without intracranial bleeding). In 4 of the 12 patients the hyperamylasemia was of pancreatic origin: 1 patient with cerebral ischemia, 1 patient with spontaneous cerebral hemorrhage, 1 patient with head injury and intracranial bleeding, and 1 patient with head injury without intracranial bleeding. The incidence of hyperlipasemia was 7% (6 of the 88 patients: 1 patient with cerebral ischemia, 2 with spontaneous cerebral hemorrhage, and 3 with head injury without intracranial bleeding). We conclude that hyperamylasemia is more frequent than hyperlipasemia in patients with an altered state of consciousness due to head injury or stroke and is usually of non-pancreatic origin. This knowledge may save these patients from invasive and costly examinations.

Systemically circulating oxidative species in human deep venous thrombosis

To investigate the hypothesis that plasmatic changes of lipoperoxidative markers are associated with deep venous thrombosis (DVT), peripheral venous blood samples were obtained from 10 patients with venographically proven DVT before starting anticoagulant therapy, and 36+/-3 and 60+/-3 hours later. Values of myeloperoxidase (MPO), 4-hydroxynonenal (HNE) and malondialdehyde (MDA) were compared with those of 10 age-matched control subjects. Despite individual variations, mean plasma MPO level was higher in the DVT group (p < 0.01), as were average plasma MDA (p < 0.001) and HNE (p < 0.01) levels. Separate analysis of the DVT cases showed that higher values of MDA, HNE and MPO were found in patients with either co-morbid diseases or clinically silent pulmonary embolism (PE). Good evidence exists for considering DVT a condition associated with an apparently excessive free radical production not buffered by efficient defence systems. A role of DVT itself cannot be excluded, but PE or other co-morbid diseases may participate in the oxidative stress. If confirmed in a larger series of patients, these findings could shed new light on the plasmatic changes associated with the propagation and complications of DVT, which in turn could have therapeutic implications.

Differences between longitudinal and circular smooth muscle in beta-adrenergic control of motility of isolated equine ileum

OBJECTIVE

To identify beta-adrenoceptor subtypes involved in motility inhibition of circular and longitudinal smooth muscle layers of equine ileum.

SAMPLE POPULATION

Isolated strips of equine ileum circular smooth muscle and membrane preparations from circular and longitudinal muscle layers.

PROCEDURE

Functional assays of circular muscle preparations and radioligand binding assays and measurements of cAMP production in smooth muscle membranes from circular and longitudinal layers.

RESULTS

Selective beta-adrenergic agonists exerted inhibitory effects on circular muscle preparations. Binding studies of cell membranes indicated that the density and distribution of 3 beta-adrenoceptor subtypes did not differ between longitudinal and circular muscle layers. Measurement of cAMP production in membrane preparations of longitudinal and circular muscle after selective beta-stimulation confirmed presence of the 3 adenylate cyclase-coupled beta-adrenoceptor subtypes; however, preparations from the 2 layers had differing cAMP production efficacy.

CONCLUSIONS

The data may partly explain the differing functional responses between circular and longitudinal muscle preparations.

CLINICAL RELEVANCE

Findings support the important role of beta-atypical adrenoceptors in the inhibitory regulation of equine ileum motility.

Effects of the combination antibiotic--EDTA-Tris in the treatment of chronic bovine endometritis caused by antimicrobial-resistant bacteria

The combined effects of the uterine infusion of EDTA-Tris solution and antibiotics have been evaluated in 75 cases of slight, moderate or severe bovine endometritis which did not respond to local routine antimicrobial therapy. Antibiotic-resistant bacteria were isolated from uterine swabs. The cows were divided into three groups on the basis of the severity of endometritis and treated with 100 ml of sterile EDTA-Tris solution (250 mM EDTA and 50 mM tris, pH 8) and the same antibiotic used in the first unsuccessful treatment (oxytetracycline, enrofloxacin, lincomycin-spectinomycin or amikacin). Control groups consisting of six animals treated with antibiotic alone were used. Clinical evaluations performed 2, 15, 21, 42 and 63 days after treatment revealed good therapeutic results, as 53 cows showed a complete recovery with renormalization of the subsequent oestrus cycle. Artificial insemination was followed by pregnancy in about 90% of treated cows. In control animals the second treatment performed using only the antibiotic gave variable and unsatisfactory results, particularly in animals affected by severe endometritis.

Potentiating effect of EDTA-Tris on the activity of antibiotics against resistant bacteria associated with otitis, dermatitis and cystitis

Possible synergistic effects of the combination of EDTA-tromethamine (EDTA-Tris) and three antimicrobial agents (cephaloridine, kanendomycin and enrofloxacin) against resistant Gram-positive and Gram-negative bacteria are reported. Bacteria were isolated from eight cases of chronic otitis externa, five cases of chronic dermatitis and four cases of recurrent cystitis in dogs which had previously been treated with one of the three antibiotics without success. Animals exposed to EDTA-tromethamine plus the antibiotic recovered completely within 10 days, and were controlled clinically and bacteriologically for 180 days. Local irrigation with EDTA-tromethamine solution was well tolerated and no side effects were recorded.

Identification of beta-adrenergic receptor subtypes mediating relaxation in isolated equine ileum

OBJECTIVE

To identify beta-adrenergic receptor subtypes in ileum smooth muscle of the horse.

SAMPLE POPULATION

Isolated strips of equine longitudinal ileum smooth muscle and membrane preparations from smooth muscle of the intestinal wall.

PROCEDURE

Functional assays and radioligand binding assays.

RESULTS

Relaxation of ileum longitudinal smooth muscle proved to be mainly caused by stimulation of beta-atypical and beta 2-adrenergic receptors. Binding studies on cell membranes indicated that the total beta-adrenergic receptors population consists of 54% beta-atypical, 34% beta 2- and 12% beta 1-subtypes.

CONCLUSIONS

The data suggest that sympathetic relaxation of equine ileum smooth muscle depends mainly on beta-atypical receptor subtypes activation, with a minor contribution by beta 2-subtypes.

CLINICAL RELEVANCE

The important role of beta-atypical adrenergic receptor subtypes in the relaxation of equine ileum suggests possible clinical use of selective beta-atypical receptor agonists to control intestinal disturbances.

In vitro toxicity and formation of early conjugates in Caco-2 cell line treated with clenbuterol, salbutamol and isoxsuprine

Caco-2, human intestinal cell line able to differentiate in long-term culture, has been used to assess the cytotoxicity of the beta-agonists clenbuterol, salbutamol and isoxsuprine, also used at high doses to obtain lean meat in food producing animals, and to investigate the eventual in vitro formation of early conjugates of these compounds. For this purpose, the cells have been characterized for the activity of UDP-glucuronyltransferase, which is present and increases in the differentiated cells, and for the beta-receptors' binding characteristics, which are those of beta 1 and beta 2 subtypes. Isoxsuprine was shown to be the most toxic, followed by clenbuterol and salbutamol. Conjugates have been observed after incubation of the cells both with the lowest isoxsuprine and the highest salbutamol concentrations. No conjugates were detected in the case of clenbuterol.

Plasma lipoperoxidative markers in ischaemic stroke suggest brain embolism

Plasma activity of myeloperoxidase (MPO), malondialdehyde (MDA) and 4-hydroxynonenal (HNE) was measured prior to any treatment in 50 consecutive stroke patients with acute cerebral ischaemia, as well as in 14 healthy control subjects. Mann-Whitney-Wilcoxon test for unpaired data showed greater values of MPO (p < 0.01), MDA (p < 0.01) and HNE (p < 0.05) in stroke patients compared with controls. Considering as covariates the level of consciousness (GCS < 9 vs > or = 9), possible sources of emboli (yes vs no), leukocyte count (< 10 x 10(9)/1 vs > or = 10 x 10(9)/1) and relevant comorbid diseases (yes vs no), exact multiple logistic regression analysis indicated that only the presence of possible cardiac sources of emboli was associated with changes in by-products of lipid peroxidation. If confirmed in a larger series of subjects, our results could have therapeutic implications, providing more support for the use of free radical scavengers in the acute care of stroke patients with a possible cardioembolic aetiology.

Variables associated with hospital arrival time after stroke: effect of delay on the clinical efficiency of early treatment

BACKGROUND AND PURPOSE

A limiting criterion for the eligibility of patients in clinical trials investigating acute stroke therapies is that time between onset of symptoms and arrival in the hospital should fall within the "therapeutic window." The aims of this study were to estimate hospital arrival time in an unselected sample of stroke patients, to assess the association with some clinical and demographic variables, and to evaluate the effects of the delay on the clinical efficiency of an effective treatment.

METHODS

We evaluated the delay in hospital arrival time in 189 patients (84 men, 105 women; mean age, 76.5 years) prospectively collected in the S Orsola-Malpighi Community Teaching Hospital in Bologna, Italy. Cutoffs of 2 and 5 hours were chosen to allow for hypothetical treatment within 3 and 6 hours, respectively. Exact multiple logistic regression was used to predict the delay as a function of dichotomized age, sex, symptoms on awakening, day of the week, hour of the day, area of residence, level of consciousness, and level of motor power defect. We then projected the effectiveness of tissue plasminogen activator (TPA) on disability as estimated with the aid of the odds ratio from the National Institute of Neurological Disorders and Stroke (NINDS) rt-PA Stroke Trial onto our unselected sample to evaluate clinical efficiency of treatment as a function of arrival time and of hypothetical effects of educational efforts to reduce it.

RESULTS

The mean interval between onset of symptoms and hospital arrival was 680 minutes; 59 patients (31%) arrived within 2 hours and 100 (53%) within 5 hours. Onset of symptoms when awake, drowsiness or coma, and paralysis of at least one limb were the only independent predictors of hospital arrival within 2 and 5 hours in both the total sample and the subgroup of patients who were awake at stroke onset. The effectiveness of 17%, extrapolated with the aid of the odds ratio of 1.6 of having a favorable outcome (Barthel Index > or = 95 at 3 months) in treated versus untreated patients in the NINDS rt-PA Stroke Trial, corresponded to a projected clinical efficiency of 5%. This could be doubled by hypothesizing a 100% effect of educational efforts in reducing the delay in hospital arrival time.

CONCLUSIONS

Patients with milder symptoms, for whom treatment might be more effective, were less likely to arrive in time for therapy. The proposed model of the relationship between the delay in hospital presentation after a stroke and the clinical efficiency of a given treatment might be useful for planning future clinical trials on early stroke treatment and predicting the impact of an educational program aimed at shortening arrival time.

Effects of clenbuterol as a repartitioning agent on beta-adrenoceptor concentrations in heart, bronchi and brain of veal calves

The effects induced by dietary clenbuterol (20 micrograms kg-1 body weight day-1 for 40 days) on beta-adrenergic receptor (beta-AR) subtypes in the heart, bronchial smooth muscles and the CNS of veal calves were investigated using a binding method. Clenbuterol exposure caused a significant (P < 0.05, P < 0.01, P < 0.001) decrease in beta 1-AR and beta 2-AR in both cardiac atria and ventricles of treated animals (excluding the beta 2-AR of the right atrium). Similarly, a significant (P < 0.01, P < 0.001) down-regulation of beta-AR subtypes in bronchial smooth muscles of treated calves was observed. In the CNS (cerebral cortex, hippocampus, hypothalamus and cerebellum) the down-regulation was limited to beta 2-AR, with the exception of the hippocampus in which both beta 1-AR and beta 2-AR concentrations were significantly (P < 0.05; P < 0.01) reduced. Scatchard analysis of the binding of the beta-AR antagonist, (-) [3H]CGP 12177, revealed that the down-regulation of beta-AR was not associated with any modification in binding affinity, as Kd values were unaffected by clenbuterol treatment. Data obtained indicated that prolonged clenbuterol exposure induced a remarkable beta-AR down-regulation in the heart, bronchi and brain of veal calves.