Oral and intravenous administration of nimesulide in the horse: rational dosage regimen from pharmacokinetic and pharmacodynamic data

REASONS FOR PERFORMING STUDY

The selective COX-2-inhibitor nimesulide is used extra-label in equine veterinary practice as an anti-inflammatory agent. However, there are no data on which to base the rational use of the drug in this species.

OBJECTIVES

To determine the effective COX selectivity of nimesulide in the horse, and suggest a suitable dosing schedule.

METHODS

The pharmacokinetics of nimesulide in the horse after oral administration (1 mg/kg bwt), and oral and i.v. administration (1.5 mg/kg bwt) were investigated, effects of feeding status on bioavailability determined, and plasma protein binding of the drug and its principal metabolites measured. Compartmental and noncompartmental pharmacokinetic analyses were performed. The plasma concentration-time profile was used, together with in vitro literature data on nimesulide inhibition of COX isoforms, to determine the effective COX selectivity of nimesulide in the horse, and suggest a suitable dosing schedule.

RESULTS AND CONCLUSIONS

The findings suggest that 1.5 mg/kg bwt may produce adequate clinical effects, and the dosing interval should be 12-24 h depending on condition severity. However, at that dose, the concentration in the animal exceeds the in vitro IC50 for both isoforms, so that COX-1/COX-2 selectivity is lost and side-effects due to COX-1 inhibition are a possibility. Nimesulide should therefore be used with caution in equine clinical practice.

Pharmacokinetics and Mammary Elimination of Imidocarb in Sheep and Goats

The pharmacokinetics and mammary excretion of imidocarb dipropionate, a therapeutic/prophylactic agent against a variety of tick-borne hemoparasitic diseases in domestic animals, have been investigated in sheep and goats. A commercial formulation of imidocarb di-propionate was injected i.m. at a single dose of 3 mg/kg of body weight in 7 mature lactating ewes and 8 lactating does in good health. Blood samples were collected for 48 h after administration and milk samples were collected every 12 h for 10 d. A weak cation-exchange solid-phase procedure was used to remove imidocarb from plasma. A hexane/isoamyl alcohol liquid-liquid procedure was adopted to extract the drug from the milk of sheep. The same method was used for goat milk after exposing the matrices to enzymatic digestion. The extracted samples were analyzed by HPLC. The i.m. disposition kinetics of imidocarb in the 2 species showed significant differences in the rate of elimination (0.0075 +/- 0.002 and 0.025 +/- 0.004 L/h in sheep and goats, respectively), being faster in ewes than in does. Nevertheless, a smaller area under the concentration-time curve (12.21 +/- 0.76 and 9.49 +/- 0.54 microg/mL per h in sheep and goats, respectively), a larger volume of distribution (4.18 +/- 0.44 and 7.68 +/- 0.57 L/kg in sheep and goats, respectively), and a longer mean residence time (9.07 +/- 0.77 and 14.75 +/- 2.20 h in sheep and goats, respectively) were found in goats, suggesting a more rapid and effective drug storage in tissues during the first 48 h after the injection. The concentrations of imidocarb in milk of both species were higher than in plasma. However, a fast passage through the blood-milk barrier and a high storage of imidocarb were observed in the milk of ewes, whereas the drug concentrations were not as high nor was the extent of drug penetration from blood to milk as great in the milk of goats (AUC(milk 0-48)/AUC(plasma 0-48) = 2.5 +/- 0.45 and 1.26 +/- 0.27 in sheep and goat, respectively). Despite the differences in pharmacokinetic behavior, and considering the sensitivity of pathogens to imidocarb, the same dosage regimen can be used for clinical efficacy against Babesia spp. infection in both species. In contrast, the differences in depletion of imidocarb residue in milk and the large variability in mammary drug elimination found in goats suggests that great care should be taken in defining the withdrawal time in small ruminant dairy species.

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.

Pharmacokinetics of imidocarb dipropionate in horses after intramuscular administration

The objective of this study was to determine the pharmacokinetic behaviour of imidocarb in horses following a single i.m. injection at the dose commonly administered to treat Babesia caballi infections or to prevent babesiosis. Eight horses were injected i.m. with a single dose of 2.4 mg imidocarb dipropionate/kg bwt and blood, faecal, urine and milk samples were collected. For imidocarb determination, a high-performance liquid chromatographic method (HPLC) was used after weak cation-exchange solid phase, or liquid-liquid, extraction procedures. Twelve hours after treatment, no detectable plasma concentrations were recorded in any of the treated animals. The distribution and elimination patterns of the drug suggested that it is quickly sequestrated in some storage tissues and remains in the body for a long time. Its prolonged presence in the body may confer a reservoir effect to imidocarb in some tissues, therefore making it undetectable in the plasma of animals but sufficient to produce its described therapeutic and prophylactic activities.

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.

Determination of dexamethasone in milk of dairy cows by immuno-enzymatic assay

Eight lactating cows received 3 im injections at 24 h intervals of a commercial formulation containing dexamethasone. Each treatment provided 25 microg/kg bw/d of dexamethasone acetate, equivalent to 22.6 mg of dexamethasone. Milk samples were obtained before treatment (5 d), during the treatment period, and for up to 22 milking after the last injection. The concentrations of dexamethasone in the milk samples were determined by a commercial competitive immunoenzymatic assay for corticosteroids (detection limit 0.15 ng dexamethasone/ml). The conventional therapeutic dose of dexamethasone acetate caused milk drug concentrations exceeding the tolerated maximum residue limit (0.3 mg/kg). A withdrawal time of 3-3.5 d for dexamethasone in milk provided sufficient protection for consumer health. The commercial enzyme immunoassay kit employed in this study was sufficiently sensitive, easy to use, and appropriate to monitor the use of dexamethasone in lactating animals.

The relationship between heritability and smoking habits in Crohn's disease. Italian Cooperative Study Group

OBJECTIVE

In Crohn's disease (CD), the relationship between genetic predisposition and smoking has not been well defined. The aim of this study was to compare the smoking habits at the time of the diagnosis of CD patients having familial occurrence of inflammatory bowel disease (IBD) with those of some control groups.

METHODS

In a multicenter study, 136 CD patients with a relative with IBD, 272 healthy controls matched for sex and age, 500 CD patients without familial occurrence of IBD, and 84 ulcerative colitis patients (UC) with familial occurrence of IBD were personally interviewed about their smoking habits. In addition, data for 35 healthy siblings of patients with familial CD were collected by interviewing the patients' relatives.

RESULTS

The prevalence of smokers was found significantly higher in CD patients with a family history for IBD than in healthy controls and in familial UC patients (OR 2.28 CI 1.5-3.48 and OR 5.81 CI 3.15-10.75, respectively). No significant difference was found either in the percentage of smokers or in the number of cigarettes smoked per day between familial and sporadic CD patients. Among all siblings of CD patients, 72% of affected siblings and 34% of healthy siblings were smokers, concordant with their relatives.

CONCLUSIONS

In CD patients with familial occurrence of IBD, the percentage of smokers is elevated. It is possible that in a genetically predisposed population, smoking could be an important environmental factor in determining CD or expressing this disease instead of UC.

Affinity of isoxsuprine for adrenoreceptors in equine digital artery and implications for vasodilatory action

We used isolated equine digital arteries to study the vasodilatory mechanism of isoxsuprine, and fowl caecum preparations to investigate the affinity of the drug for beta-adrenoceptors. Isoxsuprine is a potent vasodilator of arterial smooth muscle that has been precontracted by an alpha-adrenoceptor agonist such as noradrenaline (log EC50 = -6.33 [-5.98; -6.68]). The present study indicates that its effect is due to alpha-adrenoceptor blockade since: (1) after a long lasting exposure to cumulative doses of isoxsuprine the vasoconstricting action of noradrenaline cannot be restored; (2) isoxsuprine does not promote relaxation on preparations precontracted by PGF2alpha; (3) isoxsuprine shifts the dose-response curve of noradrenaline to the right; and (4) its affinity (pK(B) = 6.90 [6.60; 7.20]) in this experiment is comparable to that in noradrenaline-precontracted preparations and is 14 times lower than that of the selective alpha1-adrenergic antagonist prazosin [pK(B) = 8.04 (7.40; 8.68]). The affinity of isoxsuprine for beta-adrenoceptors was 100 times lower than that of isoprenaline when tested on fowl caecum. This preparation has a large beta-adrenoceptor and negligible alpha-adrenoceptor population concerned with the control of smooth muscle motility. Our data suggest that the alpha-mediated effect of isoxsuprine on horse arterial smooth muscle is due to higher affinity of the drug for alpha- than beta-adrenoceptors rather than low concentration or functionality of beta-sites at this site. According to these data, pure beta2-agonists seem to be more profitable tools to determine vasodilation of the arterial bed in horses legs.

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.

Disposition of antimony and aminosidine combination after multiple subcutaneous injections in dogs

The disposition of a combination of antimony (Sbv) (12.8 mg/kg) and aminosidine (AM) (10 mg/kg) in 10 healthy Beagle dogs after multiple subcutaneous injections is described. Sbvplasma concentrations were determined by atomic absorption spectrometry, and AM by ion-pair liquid chromatography, using a fluorimetric detector. Sbvreached Cmaxat 60 min, and for about 1 h plasma levels were homogeneously stabilized between 10.78 and 11.76 microgram/mL; by 12 h, Sbvplasma concentrations were close to the detection limit (0.3 microgram/mL). AM Cmaxvalues were recorded after 1 h (30.6+/-3.11 microgram/mL, mean +/- SD), and plasma levels reached values close to the detection limit (0.15 microgram/mL) between 7 and 8 h after injection. Sbvkinetic parameters did not appear modified by the presence of AM. Moreover, repeated injections of the combination did not modify the kinetic behaviour of the two drugs and did not alter the renal function of the animals. The superimposition analysis of the Sbvdata suggests that a twice daily injection of the metal at a dose of 12.8 mg/kg would be sufficient to maintain inhibitory Sbvconcentrations similar to those recorded in humans.

Suitability of the old fowl rectal caecum preparation for investigating the selectivity of beta-adrenergic drugs

We tested alpha- and beta-adrenergic drugs on isolated strips of fowl rectal caecum from 14- to 16-week-old Warren hens. Basal tone and spontaneous motility were dose-dependently reduced by isoprenaline and all the selective beta-agonists tested (except xamoterol) with the following order of potency: isoprenaline=fenoterol=procaterol=clenbuterol>dobutamine> SR58611A. The results indicate that this tissue preparation consists almost entirely of beta2-adrenoceptors. This preparation may, therefore, be considered a suitable assay for discriminating beta1- from beta2-agonists according to their selectivity.

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.

Controlled trial of oral 5-aminosalicylic acid for the prevention of early relapse in Crohn's disease

BACKGROUND

Recent data indicate that 5-aminosalicylic acid (5-ASA) is most effective in preventing relapse of Crohn's disease in patients with a short duration of remission before enrollment.

AIM

To evaluate the efficacy of oral 5-ASA treatment, started immediately after achieving steroid-induced remission, in preventing clinical relapses of Crohn's disease.

METHODS

Patients with active Crohn's disease, achieving remission on steroids, were randomized to oral 5-ASA 3 g/day or placebo, while steroids were tapered over 6 weeks. The trial was terminated after interim analysis showed a slightly higher relapse rate in the 5-ASA group, and the calculated probability of seeing a statistically significant difference by completing the study was minimal.

RESULTS

Final analysis included 117 patients (58 taking 5-ASA and 59 taking placebo; follow-up 9.2 +/- 6.5 months). Cumulative relapse rates at 6 and 12 months were 34% and 58% in 5-ASA patients and 31% and 52% in placebo patients, respectively (rate difference +0.095; 95% CI = -0.085 to +0.274). Subgroups analysis showed that 5-ASA was equally ineffective in patients with ileal, colonic or ileocolonic disease.

CONCLUSIONS

Contrary to previous results, in our study early introduction of treatment with oral 5-ASA did not prevent relapse in Crohn's disease patients treated with steroids to induce remission.

Long-term efficacy of bismuth carbomer enemas in patients with treatment-resistant chronic pouchitis

BACKGROUND

Mucosal inflammation of the ileal pouch (pouchitis) is the major long-term complication after ileal pouch-anal anastomosis for ulcerative colitis. Broad-spectrum antibiotics are the mainstay of treatment, however, 15% of patients with pouchitis have a chronic, treatment-resistant disease.

AIM

To determine the safety and efficacy of bismuth carbomer enemas in achieving and maintaining remission in treatment-resistant chronic pouchitis.

METHODS

Twelve patients with treatment-resistant chronic pouchitis were treated nightly for 45 days with enemas containing elemental bismuth complexed with carbomer. Diagnosis of pouchitis and response to treatment were evaluated with the Pouchitis Disease Activity Index (PDAI), which includes clinical, sigmoidoscopic and histological criteria. Serum bismuth concentrations were determined by atomic absorption.

RESULTS

Ten of 12 patients (83%) went into remission, with a significant decrease of mean total PDAI score from 12 (range 9-15) to 6 (4-15) (P < 0.002), and were continued on bismuth carbomer enemas administered every third night for 12 months. Patients were monitored clinically, sigmoidoscopically and histologically every 2 months for evidence of recurrence (increase > or = 2 in the clinical symptom portion of the PDAI). Six of 10 patients (60%) were able to maintain remission throughout the 12-month trial; 4/10 had an exacerbation, two of which occurred soon after discontinuing daily treatment. Serum bismuth levels were negligible in all patients and no side-effects were registered.

CONCLUSIONS

Our findings suggest that bismuth carbomer enemas are safe and effective in achieving and maintaining remission in patients with treatment-resistant chronic pouchitis.

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.

Relationship between site of disease and familial occurrence in Crohn's disease

Concordance in the extent of disease among the family members of patients with Crohn's disease has not been widely investigated. Furthermore, the relationship between the site of the disease and familial occurrence has never been studied. Our aim was to evaluate the familial occurrence of Crohn's disease in the various sites. Nine hundred thirty-four patients with Crohn's disease, observed consecutively in two gastrointestinal departments, were investigated to determine first-degree familial incidence (in both Crohn's disease and ulcerative colitis). Whenever two or more members were attending the same clinic, only one was regarded as a propositus. The analysis, therefore, was carried out on 882 patients. The exact site of the disease was determined in all patients either at diagnosis or during the follow-up by colonoscopy and by small bowel enema. The rate of concordance in the extent of disease and familial occurrence in the various sites was evaluated and the difference was calculated by chi-square test. Sixty-one propositi were identified among all the patients. Forty-nine had familial occurrence for the same disease (concordant patients), whereas 12 had at least one relative with ulcerative colitis (discordant patients). In 44 propositi with only one relative affected, the rates of concordance in the extent of the disease were 84, 68, 18, and 0% respectively, for the ileum, the ileum-right colon, the ileum-total colon, and the colon. The number of propositi in the various sites was as follows: 4 of 162 (2.4%) patients with the disease located in the colon, 1 of 9 (11%) with the jejunum site, 24 of 380 (6.3%) with the ileum site, 16 of 165 (9.7%) with the ileum and right colon site, and 16 of 164 (9.7%) with the ileum and total colon site. The chi-square values of propositi distribution among other sites and the colon was, respectively, as follows: jejunum, 2.2 (N.S.); ileum, 3.4 (P = 0.06); ileum and right colon, 7.4 (P = 0.006); and ileum and total colon, 7.4 (P = 0.006). This study shows a pronounced concordance in the site of the disease for family members with Crohn's disease and suggests that familial occurrence in Crohn's disease is less frequent when the disease is located in the colon rather than elsewhere.

Pharmacokinetics and dosing regimen of aminosidine in the dog

The kinetic behaviour of the aminoglycoside aminosidine, given at 15 mg/kg intravenously, intramuscularly and subcutaneously, was studied in 5 dogs to determine the appropriate dosage schedule. The pharmacokinetic behaviour of aminosidine in dogs was similar to that in other species, except that it was eliminated more slowly (beta = 0.007 +/- 0.0003 min-1). Intramuscular and subcutaneous administration produced peak serum concentrations (Cmax[im] = 32 +/- 6.4 micrograms/ml; Cmax[ac] = 36 +/- 3.4 micrograms/ml) and times to peak concentration (Tmax = 60 min for both) that did not differ significantly; and neither compartmental nor non-compartmental analysis revealed any significant differences between any of the kinetic parameters obtained for these two extravenous routes of administration. Comparison of these results with previously published data suggests that aminosidine given once daily at 15 mg/kg would be as effective all, and safer than, the two or three daily administrations commonly employed in dogs.

Disposition of antimony and aminosidine in dogs after administration separately and together: implications for therapy of leishmaniasis

The pharmacokinetic behaviour of aminosidine (15 mg kg-1) and antimony (25.65 mg kg-1 as N-methylglucamine antimoniate), administered subcutaneously either separately or together was studied on four dogs. The results demonstrated that antimony (Sb) did not significantly modify the kinetics of aminosidine (AM) but that the kinetic behaviour of the metal was markedly influenced by the antibiotic, as shown by the differences in mean residence time (MRT), elimination rate constant (Kel) and area under the curve (AUC) with and without the antibiotic (MRT[Sb] = 243.8 +/- 29.5 minutes, MRT[Sb+AM] = 1067.9 +/- 199.2 minutes; Kel[Sb] = 0.008 +/- 0.001 min-1, Kel[Sb+AM] = 0.0015 +/- 0.0003 min-1; AUC[Sb] = 21,024.6 +/- 4448.5 micrograms min ml-1, AUC[Sb+AM] = 130,478.5 +/- 30,481.7 micrograms min ml-1). The persistence of high serum concentrations of antimony when it was administered with aminosidine suggests that the therapeutic doses commonly used should be reduced and that the interval between administration should be increased to avoid the metal reaching toxic concentrations.

Familial adenomatous polyposis and inflammatory bowel disease associated in two kindreds

We describe two families in which some members are affected by familial polyposis syndrome: in one family a case of ulcerative colitis and in the other a case of Crohn's disease were found. This is the first report about this family association, but in our opinion the fact that two cases have been found in one series suggests that this association could be more frequent than reported so far. The research for a genetic pattern of inflammatory bowel disease could be addressed towards chromosome 5.

Effects of new fish oil derivative on fatty acid phospholipid-membrane pattern in a group of Crohn's disease patients

Fish oil has been recently proposed as a possible effective treatment in inflammatory bowel disease (IBD); however, a lot of annoying side effects (ie, belching, halitosis, diarrhea, etc) affect patient compliance. We carried out a study of patient tolerance in a group of Crohn's disease (CD) patients with a new fish oil derivative consisting of 500-mg capsules of eicosapentaenoic-docosahexaenoic (EPA 40%-DHA 20%), a free fatty acid mixture (Purepa), and we also evaluated its incorporation into phospholipids, both in plasma and in red cell membranes. Five groups of 10 CD patients in remission received nine Purepa capsules daily in four different preparations (A: uncoated, B: coated, pH 5.5; C: coated, pH 5.5, 60 min time release; D: coated, pH 6.9) and 12 x 1-g capsules daily of a triglyceride preparation (Max-EPA, EPA 18%-DHA 10%), respectively. We coated three of the four Purepa preparations in order to delay the release of contents in an attempt to minimize the side effects. After six weeks of treatment, the group taking Purepa capsules, coated, pH 5.5, 60 min time release (group C) showed the best incorporation of EPA and DHA in red blood cell phospholipid membranes (EPA from 0.2 to 4.4%, DHA from 3.7 to 6.3%), and no side effects were registered, whereas in all other groups side effects were experienced in 50% or more of subjects. This new preparation will make it possible to treat patients for long periods.

In vitro effects of tachykinins on the smooth musculature of horse gut

The contractile effects of the tachykinins eledoisin, substance P and neurokinin A and B were investigated in vitro on circular and longitudinal muscle strips from horse duodenum, ileum and colon. Circular smooth muscle of the small intestine was highly responsive, large intestine circular smooth muscle less so, while longitudinal muscle from all gut segments was much less sensitive. pD2 values and intrinsic activities on small intestine circular muscle indicated differences in receptor distribution between the duodenum and ileum: NK3 and a smaller number of NK2 receptors being present in the duodenum, and NK2 receptors predominating in the ileum. Notwithstanding this, eledoisin and neurokinin B were the most active substances on duodenum and ileum, respectively. These findings suggest that tachykinins may play a role in equine gastrointestinal pathophysiology.

Comparative pharmacokinetics of ampicillin-sulbactam combination in calves and sheep

The pharmacokinetics of ampicillin and sulbactam administered in combination were studied in calves and sheep. The animals were administered an aqueous solution of ampicillin/sulbactam (2:1, w/w) intravenously and intramuscularly at doses of 13.2 and 6.6 mg.kg-1, respectively. A microbiological method was used to detect ampicillin, and HPLC was used to detect sulbactam in serum. Following intravenous (i.v.) administration, the distribution phases were rapid and similar (about 15 min) for both drugs in both species, whereas sulbactam in calves and ampicillin in sheep showed a faster elimination rate. After intramuscular (i.m.) administration both drugs showed peak concentrations higher in calves than in sheep; the peak time of sulbactam was shorter in calves than in sheep. No other significant differences in the pharmacokinetics of the combination were observed between the species after i.m. injection. The mean residence and absorption times, calculated by non-compartmental analysis, for both calves and sheep suggested that the differences in ampicillin and sulbactam pharmacokinetics could be attributable to the different molecular structures.

Steroid treatment in active Crohn's disease: a comparison between two regimens of different duration

BACKGROUND

Steroids are highly effective in active Crohn's disease; clinical relapse following steroid withdrawal, however, is frequent. We used two steroid regimens of different duration in order to compare their efficacy in inducing and maintaining clinical remission.

METHODS

Seventy patients with active Crohn's disease were treated with methylprednisolone 40 mg/day i.m. for 3 weeks and then with two different regimens of tapering dosage: one for a further 4 weeks and another for a further 12 weeks.

RESULTS

Steroid therapy induced remission within 3 weeks in 91% of the whole group of patients; at the end of each protocol remission rates were 85% of patients in the group treated for the shorter period and 87% of those treated for the longer period (difference 2%, CI = -14 to 18, P = NS); remission rates within 6 months after stopping steroids were 53% and 37% respectively (difference 16%, CI = -9 to 41, P = NS).

CONCLUSIONS

No significant differences were found between the two regimens. Multiple courses of steroid treatment in the previous 3 years and a short time interval following previous steroid treatment seem to be risk factors for relapse.

Effectiveness of 5-aminosalicylic acid for maintaining remission in patients with Crohn's disease: a meta-analysis

OBJECTIVES

We conducted a meta-analysis of the published randomized clinical trials to evaluate the effectiveness of 5-aminosalicylic acid (5-ASA) for maintaining remission in inactive Crohn's disease.

METHODS

The trials were identified by standard computerized techniques for literature search. All studies included in the meta-analysis were aimed at evaluating the effectiveness of 5-ASA in comparison with a control group receiving either no treatment or placebo.

RESULTS

Our meta-analysis of five clinical trials published as full-length articles indicates that 5-ASA significantly reduces the relapse frequency in patients with inactive Crohn's disease [odds-ratios (95% CI): 0.56 (0.37-0.84) at 6 months, 0.47 (0.33-0.67) at 12 months, 0.53 (0.38-0.73) at 24 months]. The pooled relapse-free rates in the treatment group were 91% at 6 months, 84% at 12 months, and 72% at 24 months; the corresponding rates in the control group were 77%, 60%, and 52%. A second meta-analysis, conducted using the additional information deriving from four randomized trials published as abstracts, gave essentially the same results.

CONCLUSIONS

Whereas our meta-analysis shows that the effectiveness of 5-ASA is statistically significant, a simple pharmacoeconomic assessment indicates that the cost for preventing each relapse can lie between $4,000 and $10,000. This cost compares favorably with the average cost for treating a relapse.

Pharmacokinetics of N-methylglucamine antimoniate after intravenous, intramuscular and subcutaneous administration in the dog

The pharmacokinetic profile of antimony in dogs was defined by administering it intravenously, intramuscularly and subcutaneously as N-methylglucamine antimoniate at a dose of about 25.65 mg of antimony kg-1 bodyweight. The results showed a different half-life for the three routes of administration: 20.5, 42.1 and 121.6 minutes for the intravenous, intramuscular and subcutaneous routes, respectively; peak time values (Tmax) were also different for the intramuscular (90 to 120 minutes) and subcutaneous (210 to 240 minutes) injection. The apparent bioavailability of antimony was > 100 per cent for the intramuscular and 100 per cent for the subcutaneous routes. The data obtained showed a relevant difference in the behaviour of the drug in the dog in comparison to that in humans.

Zinc supplementation restores plasma concentrations of zinc and thymulin in patients with Crohn's disease

The aim of this work was to evaluate whether oral supplementation with zinc sulphate (ZnSO4) could restore thymic endocrine function in patients with Crohn's disease who showed decreased plasma concentrations of zinc and active thymulin, a zinc-dependent thymic hormone. Twenty-seven patients in clinical remission were randomly assigned to receive, for 3 months, one of the following treatments: 60 mg/day ZnSO4; 200 mg/day ZnSO4 or placebo. Plasma thymulin activity and zinc concentrations significantly increased only in patients treated with 200 mg/day ZnSO4. Lymphocyte subpopulations, within the range of normality before zinc supplementation, were unaffected by any of the administered treatments. In conclusion, low plasma concentrations of zinc and thymulin in Crohn's disease patients were restored by the administration of high doses of zinc.

Comparison of scintigraphy with indium-111 leukocyte scan and ultrasonography in assessment of X-ray-demonstrated lesions of Crohn's disease

The aim of this study was to compare the results obtained with an indium-111 scan with those obtained with less expensive and harmless ultrasonography to evaluate the location and inflammatory activity of Crohn's disease. Thirty-one patients previously studied with x-ray underwent abdominal 111In scans and ultrasonography (US). Sensitivity and specificity of US in detecting lesions seen with 111In scan were 77% and 92.8%, respectively. Sensitivity and specificity of 111In scan in detecting x-ray-defined lesions were 69.2% and 92.7%; the figures for US were 73% and 93.3%, respectively. Considering the evaluation of disease activity, ultrasonographic bowel wall thickness was significantly related to scintigraphic intensity of emission (r = 0.75 P < 0.01). Our experience suggests that US provided information about the location and inflammatory activity of lesions similar to that obtained from 111In scan.

Changes in splanchnic hemodynamics in inflammatory bowel disease. Non-invasive assessment by Doppler ultrasound flowmetry

An increase in splanchnic blood flow in both arterial and venous beds has been demonstrated in inflammatory bowel disease (IBD) by means of angiographic and scintigraphic studies. Doppler ultrasound (US) enables a non-invasive evaluation of splanchnic arterial inflow in the superior mesenteric artery (SMA) and of venous outflow in the portal vein. The aim of this study was to assess the role of Doppler US in detecting changes in the hemodynamic variables measured in patients with IBD. Forty-five patients with IBD were studied, including 22 with Crohn's disease (CD) and 23 with ulcerative colitis (UC), and compared with 45 matched normal subjects. The mean velocity of portal flow (Vmean) and the resistance index (RI) of the SMA were evaluated by Doppler US. In CD the Vmean of portal flow was significantly higher in patients with active disease than in controls (p less than 0.001) and patients with inactive disease (p less than 0.001). The RI of the SMA was significantly lower in active disease than in controls (p less than 0.005), but no significant difference was noted between active and inactive CD. Also in UC, the Vmean of portal flow was significantly higher in patients with active disease than in controls (p less than 0.01) and patients with inactive disease (p less than 0.05). The RI of the SMA was significantly lower in active disease than in controls (p less than 0.005) and in patients with inactive disease (p less than 0.005). Doppler follow-up studies were carried out in 10 patients after initiation of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Dipsogenic-like and behavioural effects of bombesin administered intracerebroventricularly to sheep

Bombesin administered intracerebroventricularly both by bolus injection (3.0, 6.0, 12.5, 25.0 and 50.0 ng kg-1) and slow infusion (0.4, 0.8 and 1.6 ng kg-1 min-1 for 30 min) potently and promptly stimulated water intake in sheep. This effect was dose dependent and bombesin was slightly more potent than angiotensin II (on a molar basis); both caused behavioural alterations (scratching and licking) in treated animals. Intravenous bolus injections of bombesin at doses up to 2500 ng kg-1 did not elicit either dipsogenic-like or behavioural effects, unlike angiotensin II. The receptor antagonist of angiotensin II, saralasin, provoked drinking in sheep at doses of 18.7, 37.5 and 75.0 ng kg-1 by intracerebroventricular bolus injection. These results surprisingly revealed that bombesin, a potent inhibitor of water intake in other mammals (rats and pigs), exerted in sheep dipsogenic-like effects similar to those in pigeons and ducks.

The effects of caerulein on exocrine pancreatic secretion in pigs

Caerulein administered to anaesthetized pigs by slow i.v. infusions at doses of 0.5, 1.0 and 2.0 ng kg-1 min-1 for 30 min, stimulated pancreatic juice production, increased the protein content of the juice and enhanced its amylolytic, lipolytic and proteolytic activities. In a single experiment, an i.v. infusion of secretin (0.001 U kg-1 min-1) lasting through the whole experimental time, provoked potentiation of the caerulein stimulatory effects on pancreatic juice production, protein content and amylolytic activity.

Effects of Caerulein on exocrine pancreatic secretion in sheep

caerulein administered by slow intravenous infusion at increasing dosage rates (0.1, 1.0, 5.0 and 10.0 ng/kg/min X 30 min) stimulated pancreatic juice production in sheep as well as the protein content, the amylolytic, the lipolytic and proteolytic activities of pancreatic juice samples collected at 30 min intervals. A long lasting (300 min) infusion of a high dose of Caerulein by subcutaneous route elicited stimulatory effects with reduced intensities, slower onsets but more sustained durations than those produced by the same dose level administered intravenously.