Gastric ulcers in standardbred racehorses: prevalence,lesion description,and risk factors

This study was performed to estimate the prevalence of gastric ulcers in Standardbred racehorses, to describe the lesion score and location, and to identify potential risk factors. Two hundred seventy-five (275) Standardbred horses from 5 training centers and 2 racetracks in Quebec, Canada, were studied. Historical data for the 2 months before examination were recorded for each horse, and the presence of gastric ulcers was determined by gastroscopy. A previously reported scoring system that used grades 0-3 for gastric lesions was used. Overall, 121 horses (44.0%; 95% CI, 38.1-50.1%) had gastric ulcers. The prevalence of gastric ulcers was significantly higher (P < .0001) in actively racing horses (63.3%; 95% CI, 54.7-71.2%) than in horses at rest. Multivariate analysis defined that horses in racing (OR = 9.29; 95% CI, 3.55-24.3) were significantly more likely to have gastric ulcers than horses at rest and that trotters (OR = 2.23; 95% CI, 1.28-3.86) were more likely to have gastric ulcers than pacers. The number of lesion sites (P < .0001) and poor body condition (P < .0001) were significantly associated with lesion scores. Gastric ulcers are highly prevalent in Standardbred racehorses. Furthermore, actively racing horses and trotters are more likely to have gastric ulcers. Also, poor body condition in Standardbred racehorses may be an indication that gastric ulcers are present and that lesion scores are high. The cause-and-effect relationship between poor body condition and the presence of gastric ulcers is unclear.     

Chemical restraint of peccaries with tiletamine/zolazepam and xylazine or tiletamine/zolazepam and butorphanol

Objective To evaluate the use of a combination of tiletamine/zolazepam and xylazine (TZX) in collared and white‐lipped peccaries and to compare its efficacy as an anesthetic technique with that of tiletamine/zolazepam and butorphanol (TZB). Study design Prospective experimental trial. Animals Seven white‐lipped peccaries (Tayassu pecari) (four females and three males) and four collared peccaries (Tayasu tajacu) (two males and two females). Methods Animal immobilization was attempted with TZX and TZB (IM) on two different occasions. Heart and respiratory rates (HR, RR), rectal temperature (RT), sedation, muscle relaxation, posture, auditory response and analgesia were evaluated every 15 minutes during immobilization. Induction, anesthesia, standing and walking time were determined after drug administration. Results Doses for white‐lipped peccaries were 1.23 ± 0.26 mg kg^?1 (mean ± SD) of TZ and 1.23 ± 0.26 mg kg^?1 of X, and 1.46 ± 0.09 mg kg^?1 of TZ and 0.14 ± 0.008 mg kg^?1 of B; doses for collared peccaries were 1.51 ± 0.29 mg kg^?1 of TZ and 1.51 ± 0.29 mg kg^?1 of X and 1.68 ± 0.02 mg kg^?1 of TZ and 0.17 ± 0.002 mg kg^?1 of B. In white‐lipped peccaries, both drug combinations provided a smooth induction and good immobilization for more than an hour. Anesthesia and standing times were significantly longer in animals given TZB, whereas walking time was significantly longer in animals given TZX. A significant decrease in HR was observed with both treatments. Respiratory rate decreased significantly with TZX, but the rate remained higher than with TZB. Induction and recovery quality in white‐lipped peccaries was better with TZB than with TZX. Neither protocol provided adequate immobilization in collared peccaries. Conclusion and clinical relevance At the doses described, TZB is effective in providing a long period of immobilization, whereas TZX is adequate for short to medium immobilization in white‐lipped peccaries. Neither drug combination was effective in collared peccaries at the doses given.     

Myxozoans infecting the sharptooth catfish, Clarias gariepinus in the Okavango River and Delta, Botswana, including descriptions of two new species, Henneguya samochimensis sp. n. and Myxobolus gariepinus sp. n

During a recent investigation of parasites infecting fishes from the Okavango River and Delta, Botswana (southern Africa) fourteen sharptooth catfish, Clarias gariepinus (Burchell, 1822) (Siluriformes: Clariidae) were examined for the presence of myxozoan infections. Results revealed the presence of two species of the genus Henneguya Thélohan, 1895 and one species of the genus Myxobolus Bütschli, 1882 infecting this fish host. Two of the sampled fish exhibited large plasmodia of Henneguya suprabranchiae Landsberg, 1987 in the cartilage of the accessory breathing organ, another two individuals were infected with H. samochimensis sp. n. plasmodia in the gills and another three individuals revealed an infection with Myxobolus gariepinus sp. n. plasmodia in the ovaries.     

Structure-activity relationship study of alkynyl ether insecticide synergists and the development of MB-599 (verbutin)

Structure-activity relationships of aryl alkynyl synergists of the general formula of Ar-Q-R, where Q represents a bridging structure, were studied using a standardised testing system and Relative Potency values. Ethers, esters, oxime ethers, amides and amines were prepared and evaluated. The length of the R-alkynyl chain, the role of the bridge and the substitution of the aromatic ring were examined systematically. The most potent compounds possessed an aromatic ring connected via a bridge of three atoms to an alkynyl chain, forming together a linear side-chain of six atoms. Several highly potent compounds were synthesised of which one (MB-599; proposed common name verbutin) was selected for development as a selective insecticide synergist in crop protection. Its high potential at practical insecticide:synergist ratios makes possible the reduction of the total amount of insect-control chemicals applied, and its use as an additive to produce new formulations of existing insecticides makes it highly advantageous in resistance management, giving a new tool to sustain the effectiveness of a wide range of insecticides. A product containing a (1+1) mixture of verbutin and beta-cypermethrin was launched in Hungary in 2002.     

Use of volumetric capnography to identify pulmonary dysfunction in horses with and without clinically apparent recurrent airway obstruction

OBJECTIVE: To investigate whether volumetric capnography indices could be used to differentiate between horses without recurrent airway obstruction (RAO) and horses with RAO that were in clinical remission or that had clinically apparent RAO. ANIMALS: 70 adult Swiss Warmblood horses (20 used for pleasure riding and 50 used for dressage or show jumping). PROCEDURE: Horses were allocated to 4 groups on the basis of history, clinical signs, results of endoscopy, and cytologic findings (group 1, 21 healthy horses; group 2, 22 horses with RAO that were in remission; group 3, 16 horses with mild RAO; group 4, 11 horses with exacerbated RAO). Expiratory volume and CO2 curves were recorded by use of a computerized ultrasonic spirometer. Volumetric capnograms were plotted, and derived indices were calculated. RESULTS: Dead-space volume (VD) was calculated by use of the Bohr equation (VD(Bohr)) and for physiologic VD (VD(phys)). Ratios for VD(Bohr) to expiratory tidal volume (VT) and VD(phys) to V(T) as well as an index of effective CO2 elimination were significantly different among groups of horses. Age and use of the horses also significantly affected volumetric capnography indices. CONCLUSIONS AND CLINICAL RELEVANCE: Ratios of VD(Bohr) to VT and VD(phys) to VT as well as an index of effective CO2 elimination were sufficiently sensitive measures to distinguish between healthy horses and horses with RAO in remission. To optimize the ability of volumetric capnography indices to differentiate among horses in heterogeneous populations, it is important to account for effects of age and specific use of the horses.     

Population pharmacokinetics of marbofloxacin in aqueous humor after intravenous administration in dogs

OBJECTIVE: To evaluate, by use of population pharmacokinetics, the disposition of marbofloxacin in the aqueous humor after IV administration in dogs and identify its potential usefulness in the prophylaxis and treatment of intraocular infection. ANIMALS: 63 dogs. METHODS: Dogs received a single dose of marbofloxacin (2 mg x kg(-1), IV) at various time intervals before cataract surgery. Aqueous humor and blood samples were collected at the beginning of surgery. Marbofloxacin concentrations were measured by high-pressure liquid chromatography. Data were analyzed with a nonlinear mixed-effect model and, by use of population pharmacokinetic parameters, the time course of aqueous humor concentration was simulated for single doses of 3, 4, and 5.5 mg x kg(-1) IV. Pharmacodynamic surrogate markers and measured aqueous humor concentrations were used to predict in vivo antimicrobial activity. RESULTS: A maximum marbofloxacin concentration of 0.41 +/- 0.17 microg x mL(-1) was reached in the aqueous humor 3.5 hours after IV administration. In the post-distributive phase, marbofloxacin disappeared from aqueous humor with a half-life of 780 minutes. The percentage penetration into the aqueous humor was 38%. Predictors of antimicrobial effects of marbofloxacin (2 mg x kg(-1), IV) indicated that growth of the enterobacteriaceae and certain staphylococcal species would be inhibited in the aqueous humor. Marbofloxacin administered IV at a dose of 5.5 mg x kg(-1) would be predicted to inhibit growth of Pseudomonas aeruginosa and all strains of staphylococci but would not eradicate streptococcal infections. CONCLUSIONS AND CLINICAL RELEVANCE: Marbofloxacin administered IV can penetrate the aqueous humor of canine eyes and may be suitable for prophylaxis or treatment of certain anterior chamber infections.     

Cerebellar cortical abiotrophy in American Staffordshire terriers: clinical and pathological description of 3 cases

Three American Staffordshire Terriers were presented with gait abnormalities and loss of balance at the age of 4.5 (female) and 6 years (2 males). The onset varied between 3 and 5 years of age and the clinical signs were slowly progressive. The neurological examination revealed symmetrical generalized cerebellar ataxia with hypermetria, stiffness, and loss of balance with no evidence of paresis. The menace reflex was decreased in one dog and absent in another. A positional nystagmus was found in two dogs. The dogs were euthanized and a histopathological examination of each brain was performed. Pathological changes were confined to the cerebellum. The main finding was loss of Purkinje cells, as well as depletion of granular cell bodies and shrinkage of the granular and molecular cell layer. These findings are consistent with cerebellar cortical abiotrophy. A genetic basis is supposed, but the mode of inheritance is not determined yet. In contrast to some spinocerebellar ataxias in humans, the cause of Purkinje cell degeneration in cerebellar cortical abiotrophy of dogs is not known.     

Quantitative changes in the normal and apoptotic thymocytes of pigs treated with anabolic doses of the beta2 adrenergic agonist clenbuterol

Although the beta2 adrenergic agonists have been seen to have important effects on the mechanisms regulating the development and death of T-cells in the thymus, the side-effects on the immune system of anabolic treatments of these substances have hardly been considered. In order to evaluate the effects exerted by the beta2 adrenergic agonist clenbuterol on the thymocyte population, the thymus of eight pigs treated with anabolic doses of this substance was studied by morphometric methods, regarding apoptotic (terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL)-positive) and normal (TUNEL-negative) cells. The thymus of another eight pigs fed without clenbuterol served as a control. The clenbuterol treatment had a clear effect on the thymocyte size, decreasing their mean nuclear area. The T-cell apoptosis index was also affected by the clenbuterol, significantly increasing the apoptosis percentage in the treated group with respect to the control. In the light of our results, the clenbuterol induced thymocyte apoptosis throughout the thymus and caused morphometric changes in the thymocyte population, which was in line with the immunosuppressive role attributed to other beta2 adrenergic agonists.     

Factors affecting the detachment rhythm of engorged Boophilus microplus female ticks (Acari: Ixodidae) from Charolais steers in New Caledonia

As in most parts of the world where the cattle tick Boophilus microplus is established, resistance of ticks to acaricides occurs in New Caledonia. In order to implement laboratory resistance tests on larvae, engorged females collected in suspected farms are necessary. Investigations on the detachment schedule of the engorged females were conducted to explain certain field situations such as the lack or scarcity of engorged females on highly infested cattle driven from the pasture to the pen in the morning. Three experiments on Charolais steers naturally infested on pastures showed that: (1) engorged female burdens at sunrise are similar whether the steers spend the night in pasture or in a pen; (2) compared with steers maintained in a pen, morning detachment of females increases when the steers stay on the pasture or move from the pasture to the pen; (3) detachment rhythm of engorged females on steers staying the morning in a pen, is not influenced by feeding activity or exposition of steers to sun; (4) detachment occurs earlier for females attached on anatomical sites exposed to sun, and earlier from these sites for the steers in pasture or walking than for steers in a pen.     

Gene discovery in Eimeria tenella by immunoscreening cDNA expression libraries of sporozoites and schizonts with chicken intestinal antibodies

Specific antibodies were produced ex vivo from intestinal culture of Eimeria tenella infected chickens. The specificity of these intestinal antibodies was tested against different parasite stages. These antibodies were used to immunoscreen first generation schizont and sporozoite cDNA libraries permitting the identification of new E. tenella antigens. We obtained a total of 119 cDNA clones which were subjected to sequence analysis. The sequences coding for the proteins inducing local immune responses were compared with nucleotide or protein databases and with expressed sequence tags (ESTs) databases. We identified new Eimeria genes coding for heat shock proteins, a ribosomal protein, a pyruvate kinase and a pyridoxine kinase. Specific features of other sequences are discussed.