Reducing exposure to pathogens in the horse: a preliminary study into the survival of bacteria on a range of equine bedding types.

AIMS: To compare the rate of growth of four microbial strains that cause disease in the horse, on four commonly used types of bedding. The moisture-holding capacity of each bedding type was also tested. METHODS AND RESULTS: Microbial strains included Streptococcus equi, Streptococcus zooepidemicus, Fusobacterium necrophorum, Dichelobacter nodosus and Dermatophilus congolensis. The bedding types tested were Pinus sylvestris (Scots pine shavings), Pinus nigra (Corsican pine shavings), Picea sitchensis (Sitka spruce shavings), Cannabis sativa (hemp) and chopped wheat straw. A suspension of each microbial strain was spread in triplicate on agar media and incubated in its optimal growth conditions. The viable count (colony-forming unit per ml) was determined for each bacterial strain for the five different bedding types. Pinus sylvestris bedding resulted in significantly less (P = 0·001) bacterial growth of all strains tested. CONCLUSIONS: Factors resulting in the inhibition of bacterial growth include the antibacterial effects reported in the Pinacea family and the physical properties of the bedding substrate. Research is currently focussed on the diagnosis and management of disease. Prevention of disease is also important for matters of biosecurity. Strategies should include the provision of a hygienic environment and the use of specific types of bedding. SIGNIFICANCE AND IMPACT OF THE STUDY: Bedding choice has implications for global equine health and disease prevention as well as potential benefits in other animal species.

[Drug therapy for diabetes mellitus during pregnancy and breastfeeding in the beginning of 21 century: status quo and new challenges].

Diabetes mellitus is frequent during pregnancy and is associated with substantial risks both for the mother and the newborn. An adequate therapy ensures the normal course of pregnancy and delivery and postnatal development of the baby. Insulin, for its well known safety record, has long been considered the drug of first choice for achieving optimal glycemic control in pregnant women. Pregnancy is an indication for intensive insulin therapy. The pre-mixed insulins are not recommended due to their inability to provide the needed therapeutic flexibility during the different periods of pregnancy. The short acting insulin analogue aspart is currently registered for meal-time use in basal therapy with NPH insulin. The long-acting analogues glargine and detemir are still investigated clinically and for the moment are only used off label in pregnancy. Maternal hypoglycemia, the need of injection and the high cost are the main drawbacks of insulin therapy. Evidence has accumulated in recent years that some oral antidiabetics are as efficacious and safe as insulin in gestational diabetes. Metformin and glibenclamide are now increasingly viewed as a rational alternative to insulin therapy--a treatment both preferred by the women and a less expensive one, during pregnancy and breastfeeding.

Anxiolytic-like effect of Aronia melanocarpa fruit juice in rats.

The main biologically active constituents of Aronia melanocarpa fruit juice (AMFJ) are polyphenolics, amongst them flavonoids, mainly anthocyanins. The aim of the present study was to investigate the effects of AMFJ (5 and 10 mL/kg) on anxiety using the social interaction test, on locomotor activity in the open field test and on working memory in the object recognition test in rats. AMFJ showed an anxiolytic-like effect which was demonstrated by a dose-dependent increase in the time of active social contacts between the test partners. The effects of both AMFJ doses were comparable to the effect of diazepam (1 mg/kg). AMFJ neither changed significantly horizontal and vertical locomotor activity, nor did it adversely affect working memory.

Serotonin 1B knockout mice exhibit a task-dependent selective learning facilitation.

Serotonin 1B knockout (KO) mice exhibit better spatial reference memory performance in the Morris water maze than their wild type (WT) controls. The present study was aimed at dissecting the underlying cognitive bases of this facilitation using a stepwise water maze paradigm. The performance of KO mice did not differ from WT in a single start-goal task, nor when using two opposite starts. However, KO mice exhibited better performance in stages requiring cognitive flexibility or the higher level of spatial navigation planning (standard version). In a short-term memory version of the task, no such genotype effect was observed, confirming our previous findings. These results suggest that the serotonin 1B receptor gene deletion selectively enhances learning performance when the cognitive requirement of the task is elevated.

Isoteoline, a putative serotonin antagonist, inhibits meta -chlorophenylpiperazine, but not 1-(2, -dimethoxy-4-iodphenyl)-2-aminopropane and 8-hydroxy-2-(di-n-propylamino)-tetraline-induced increase of serum prolactin levels.

Serotonin, in addition to dopamine and other factors, is known to participate in the control of prolactin (PRL) and gonadotropins secretion. Isoteoline (IST), a putative serotonin antagonist and dopamine agonist, was studied for its neuroendocrine effects on PRL, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). IST was given intraperitoneally to adult male rats at doses of 0.25, 1 and 4 mg kg(-1)alone and 30 min prior to the injection of three 5-HT agonists with preferential affinity for various receptor subtypes: meta -chlorophenylpiperazine (m CPP) for 5-HT2C; 1-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) for 5-HT2A and 8-hydroxy-2-(di- n -propylamino)tetralin (8-OH-DPAT) for 5-HT1A. m CPP (2.5 mg kg(-1)), DOI (2.5 mg kg(-1)) and 8-OH-DPAT (1 mg kg(-1)) increased the serum PRL levels to a similar value, without affecting FSH and LH concentrations. IST by itself modified neither PRL nor gonadotropins serum levels. IST antagonized the m CPP-induced elevation in serum PRL, the lowest dose being the most effective. It had no effect on DOI and 8-OH-DPAT-induced increases of PRL levels and produced no significant changes in the gonadotropins levels when used as an antagonist. The results are discussed in terms of the likely involvement of serotonin vs dopamine mechanism in the effect of IST. It is concluded that the inhibition of the m CPP-induced rise of PRL levels by IST confirmed the serotonin antagonistic activity, previously demonstrated for this compound in other studies. The present results are also suggestive of possible selectivity of this antagonism of IST for the 5-HT2C vs 5-HT2A and 5-HT1A receptors, all of which are involved in the control of PRL secretion.

Systemic chlorophenylpiperazine increases acetylcholine release from rat hippocampus-implication of 5-HT2C receptors.

The release of acetylcholine (ACh) from the hippocampus of freely moving rats was studied after the systemic and local administration of the 5-HT agonist chlorophenylpiperazine (mCPP), utilising the in vivo microdialysis coupled to HPLC. Intraperitoneally (i.p.) given mCPP at a dose of 8 mg kg(-1)increased the release of ACh from the hippocampus by approximately 96%. This effect was not observed when the agonist was delivered locally through the dialysis tube (reverse dialysis). The mCPP-induced increase of ACh release was prevented by i.p. mesulergine, a 5-HT2A/2C receptor antagonist, at a dose of 2 mg kg(-1). A similar effect was found with the i.p. administration of isoteoline-a putative serotonergic antagonist. Both mesulergine and isoteoline have been shown to prevent also the mCPP-induced increase of ACh release from rat cortex. In the cortex experiments both antagonists were inactive by themselves. In the hippocampus, however, isoteoline, unlike mesulergine, increased significantly the output of ACh when used alone. This effect was haloperidol-sensitive, which implies a possible dopaminergic mechanism. The results of the present work suggest that (i) the effect of mCPP on ACh release could be attributed to stimulation of 5-HT2C receptors located outside the hippocampus and (ii) isoteoline antagonizes this mCPP-induced effect irrespective of its own enhancing action on ACh release.

[The effect of isotheoline on mouse behavior under test conditions for detecting its anxiolytic activity]. / Vliianie izoteolina na povedenie myshei v usloviiakh testa dlia vyiavleniia anksioliticheskoi aktivnosti.

The effect of isotheolin, a glaucin derivative, on the behavior of mice was studied under conditions of a model of preference of the dark section of the chamber to the light one which is used for appraisal of the anxiolytic/anxiogenic activity of substances. Intraperitoneal injection of isotheolin in a dose range of 0.25-4 mg/kg antagonized the anxiogenic effect induced by the serotonin agonist [correction of antagonist] chlorophenylpiperazine, mCPP (4 mg/kg). In a dose of 4 mg/kg isotheolin has an anxiolytic effect on intact animals. Bearing in mind that mCPP produces its anxiogenic effect via the 5-HT2C receptors, it is suggested that the mechanism of the anxiolytic action of isotheolin is realized through its interaction with the serotoninergic system at the level of 5-HT2C receptors.

Increase of cortical acetylcholine release after systemic administration of chlorophenylpiperazine in the rat: an in vivo microdialysis study.

The changes in acetylcholine (ACh) release from the cortex of freely moving rats after systemic administration of chlorophenylpiperazine (mCPP), a 5-HT2C agonist, were measured utilising microdialysis coupled to high performance liquid chromatography. mCPP administered intraperitoneally (i.p.) increased cortical ACh release, but failed to do so when applied locally in the cortex. The effect of i.p. administered mCPP on cortical ACh release was prevented by i.p. injection of mesulergine, a 5-HT2A/2C receptor antagonist, and isoteoline, a compound previously shown to antagonize behavioural effects of mCPP. An increase of cortical ACh release was also found after the local administration of mCPP in nucleus basalis magnocellularis (NBM). The results of the present work suggest that 5-HT2C receptors located in NBM are involved in the modulation of cortical ACh release in the rat.

Absorption of lincomycin through the respiratory pathways and its influence on alveolar macrophages after aerosol administration to chickens.

A concentration of 250 mg m-3 lincomycin was administered by aerosol to 40 chickens, weighing between 1900 and 2200 g. The birds were killed in groups of five at different intervals after dosing, and the trachea, lungs and blood serum were examined for antibiotic content by bioassay. The antibiotic was present at high levels in the trachea for one to 24 hours, and significant levels were present in the lungs and serum. Respiratory macrophages were obtained from the lungs and air sacs of the chickens by lavaging through the surgically prepared trachea with a paediatric urinary catheter. The macrophages were identified by morphology as round or slightly amorphous, refractile, frequently grannular cells; they phagocytosed Staphylococcus aureus 6538.

Alkaline phosphatase activity in serum of guinea fowl bearing bone tumours induced by osteopetrosis virus strain PTS-56.

Alkaline phosphatase (AP) activities of sera from guinea fowl infected with osteopetrosis virus strain PTS-56 were investigated. Enzyme activities in birds of infected and control groups varied. AP activities in control guinea fowls, 10 to 15 weeks of age, were twice as high as those of 1-year-old birds whose growth was completed. A positive correlation was found between the intensity of virus-induced excessive bone growth and serum AP activity, which was 628 +/- 68.9 microM by the 17th week and reached 1283 + 76.8 microM by the 30th week post-infection (p.i.). Later AP activity decreased, but even at 52 weeks p.i. it was higher than that of untreated guinea fowl. The presumed high proportion of AP of bone origin of the total serum enzyme activities was supported by the low values of residual AP activity after heat inactivation at 58 degrees C (14.7 +/-3.7%) and after precipitation with wheat germ lectin (13 +/-1.2%) during the period of active bone tumour formation.

[Electron microscopic research on an experimental infection in chicks caused by the infectious bursal virus]. / Elektronnomikroskopski prouchvaniia pri eksperimentalna infektsiia na pileta s virusa na infektsiozniia burzit.

A total of 18 birds at the age of 25 days were infected intraocularly with the pathogenic strain 52/70 of the infectious bursitis virus. The bursa of Fabricius and the thymus were sampled for electron-microscopic investigations. The ultrastructural changes in the infected cells consisted in pycnosis of the lymphocyte and macrophage nuclei, vacuolization of the cytoplasm, and the production of lipid droplets as well as of inclusion bodies of varying density, myelin figures, multivericular bodies, and other irregular structures in the cytoplasm. These changes were slightly visible at the 24th hour, were characteristic at the 48th hour, and were well manifested at the 72nd hour following infection. Beside the degenerative changes in the cytoplasm of the affected cells (mainly lymphocytes) there were at the 24th hour of infection tiny-granular matter of fibre-like structure and particles within it of varying electron density. In the later phases (at the 48 h and the 72nd hour) viral particles that were either free or in the vacuoles were predominantly seen in the cytoplasm of the macrophages, having a dia of 50-60 nm and a hexagonal form, with crystalographic arrangement. It was also demonstrated that the replication of the virus of the infectious bursal infection took place in lymphocytes, and in the later stages of infection--chiefly in macrophages. These were the two main types of cells in which virus replication was seen to take place.

[Asymptomatic course of infectious bursitis in chickens]. / Bezsimptomno protichane na infektsiozen burzit pri pileta.

Morphologic and serologic studies were carried out with a total of 190 birds of three breeds (Cornish, White Plymouth Rock, and Gillink) aged 1 to 50 days, with which Gumboro disease ran a symptomless course. Gross lesions were established in 3.1 per cent of the birds only. Histopathologically, however, there were changes in the bursa Fabricii (73.6 per cent), the spleen (68.4 per cent), the thymus (10.5 per cent), and the cecal tonsils (5.2 per cent). The microscopic lesions consisted in malacia of the elements of the lympho-reticular system. Serologically, mother precipitating antibodies were found in the first 2-3 weeks following hatching. The postinfection antibodies were shown to be released in the sixth to seventh week of even later. It was demonstrated that the symptomless course of infectious bursitis in birds could be histologically and serologically diagnosed as early as the first week following hatching, whereas the morphologic changes were mostly manifested between the 36th and the 50th day of age.

[Pathomorphological studies of infectious bursitis in chickens with a subclinical infection]. / Patomorfologichni prouchvaniia na zarazniia burzit po pileta pri subklinichna infektsiia.

A total of 70 growing birds of three breed, aged 1 to 42 days in which the disease was serologically and morphologically demonstrated were studied. No apparent gross lesions were established with any of the birds. Histologically, there was in the bursa of Fabricius a drop of the lymphocytes within the lymphoreticular system of the follicles. There were in the center of the follicles histiocytes, and epithelial proliferation was seen with single follicles. The cover epithelium of the bursa presented vacuolar degeneration. The white pulp of the spleen was poorer in lymphocytes. There were in the thymus and the cecal tonsils of individual birds pseudoeosinophile leukocytes within the lymphoreticular system as well as lymphomalacia. Serologically, in birds aged 1-2 weeks high titers of antibodies were discovered (1:4 and 1:16), while in those aged 3-6 weeks the antibodies dropped--to 1:3 (with the 3-week-old ones) and to nil (in the 4-, 5-, and 6-week-old ones), which corresponded to the morphologic changes in the investigated organs. It was histologically demonstrated that the virus of infectious bursitis affects the lymphoreticular system of the birds as early as the first 20 days following hatching, which invariably has a bearing on their immune resistance.