Veterinarno-meditsinski nauki最新文献

Cytologic investigations were carried out of a total of 140 cows with regard to the vaginal mucosa in the event of disturbed functions in the course of the sexual cycle: hypofunction of the ovaries (71 animals), persisting yellow bodies (34 animals), and estral and postestral cases of metrorrhagia (35 animals). Chamov's trichromatic method was employed to stain the smears and Véznik's cytogramme method--to carry out the recordings. It was found that in the case of ovarian hypofunction the mixed type of cell pictures prevailed (47.8 per cent), followed by the estrogenic type (39.4 per cent), and the progesterone type (12.6 per cent). In the case of persisting corpora lutea the mixed type of cell picture prevailed too--64.7 per cent, while the estrogenic and progesterone types were 17.6 per cent. Featuring in the postestral and estral metrorrhagia was the estrogenic type of cell picture (51.4 per cent), while the mixed type accounted for 45.7 per cent of the cases, and the progesterone one--for 2.8 per cent. It is suggested to use the cytovaginal method in combination with the routinely employed clinical and laboratory tests for the overall evaluation of the condition of the genital system in cows.

An experiment was carried out with 7-day-old broiler birds to assess the effect of ochratoxin A on their health. A standard feed mixture, containing 4 mg/kg ochratoxin A in pure substance, was offered to the birds in the course of 21 days. No severe clinical symptoms and death cases were observed during the experimental period. However, both the growth and the development of the birds were arrested along with an increase in the relative weight of the kidneys and changes in their morphology--vascular disturbances and dystrophy more strongly manifested in the kidneys and to a weaker extent seen in the bursa of Fabricius, the thymus, and other organs.

Clinical, morphological, and histomorphological investigations were carried out of the changes taking place in the solar matrix in some more common diseases in cows raised in the conditions on the enlarged farms of industrial cattle breeding. With the traumatic aseptic inflammations of the solar matrix the nova and its effect predetermine histologically the various degrees of changes, consisting in circulation disturbances, oedema of the connective tissue, disintegration of the connective tissue bundles, divergence of the collagen fibres, mucinous dystrophy, fibrinoid-necrotic foci, and heterophilic infiltration around the blood vessels and in their wall (arteriitis and periarteriitis). In suppurative inflammations of the solar matrix the process assumes diffuse character with strongly manifested leukocytic infiltration, with the development of dystrophic necrobiotic processes. As a result of these partially or more widely expressed separation (exungulatio) of the solar horn tissue from the matrix sets in. In the initial stage of the traumatic sole ulcer are observed the signs described for an aseptic inflammation. Later on the processes assume a more strongly manifested course, involving the matrix with atrophy and necrosis, separation of the hoof horn from the matrix. With the secondary complication with pathogenic organisms the signs of purulent and necrotic inflammation are seen, resulting in an ulcus defect.

The possibilities of lymphocytes from the blood of pigs, cows, sheep and rabbits, using Lymphoprep, Polysep, and Histopaque were investigated. The conditions given by the producer firms were strictly observed when dealing with the separation media, and in cases when the results were unsatisfactory modifications were made with regard to the velocity and duration of centrifugation in carrying out the separation. The functional state of membrane receptors of lymphocytes was checked by rosette tests with erythrocytes for the detection of T-lymphocytes. It was demonstrated that lymphocytes from pig's blood are successfully isolated with all three separating media, when observing the conditions of manipulation as indicated by producer firms. With ruminants the best results were obtained with Lymphoprep. Polysep is not suitable medium for lymphocyte isolation from cow's blood; Histopaque can be used if the separation is carried out at 1880 r. p. m. for 40 minutes. Good results are obtained with Polysep with sheep's blood when the separation is performed at 1880 r. p. m. for 40 minutes. All three media can be used in isolation of lymphocytes from rabbit's blood. The isolation of lymphocytes with Histopaque must be performed by centrifugation at 1520 r. p. m. for the duration of 40 minutes. The separation media investigated do not harm the membrane receptors of lymphocytes.

It has been demonstrated phenotypically that there exists a new modificational-and-restrictional system as synthesized by the recombinant Escherichia coli tF strain. A series of passages of the T3 and T7 phages and their mutants in E. coli tF has made it possible to ascertain a specific modification of the phage DNA, with was shown to be induced by the host strain. The high level of adsorption of these phages on the cell surface of E. coli tF has ruled out the possibility of existing of a 'nonclassical' modification and restriction of DNA. In view of the further characterizing of this modificational-and-restrictional system of E. coli tF it has been comparatively studied with the already known modificational-and-restrictional systems isolated from various Escherichia coli strains. Results have shown that no identity exists between the tested systems and the one in E. coli tF. It is stated that the new modificational-and-restrictional system of E. coli tF belongs to none of the three known types of restrictional endonucleases.

A reovirus was isolated from 5-13-day-old broiler birds with signs of the so-called helicopter disease--one of the forms of the malabsorption syndrome. A number of organs were investigated (trachea, liver, spleen, bursa of Fabricius, proventricular stomach, and tendon sheath of musculus gastrocnemius). The virus was isolated from the proventricular stomach and the tendon sheath in cell cultures of chick embryo kidney as well as in 5-7-day-old chick embryos inoculated in the yolk sac. The remaining organs proved virologically negative. All organs, including the primarily positive ones, were shown to be virologically negative upon the inoculation of chick embryo fibroblast cultures and of chorioallantoic membranes of 10-11-day-old chick embryos. The isolate was identified as an avian reovirus, and was denoted with the initials R-85--on the grounds of its biologic and physico-chemical properties, of its morphology (negative-contrast electron microscopy), and of its morphogenesis (ultrathin electron-microscopic cross sections). Investigated were the histopathologic changes in chick embryos inoculated with the R-85 reovirus and the pathologic changes in the liver of spontaneously affected birds.

A total of 19 buffalo cows were used to induce superovulation following a pattern that included the use of FSH at the rate of 40 mg in the course of four days, applied twice a day and of Oestrophan at 48 hours after the beginning of treatment. Fifteen animals manifested estrus and were twice inseminated. The superovulation response of the ovaries was 4.3 +/- 0.8 yellow bodies and 0.5 +/- 0.24 follicles greater than 8 mm. A nonsurgical method was employed to obtain 24 embryos of high quality and an unfertilized ovum from 8 buffalo cows.

Studied was the dynamic of antibiotic resistance of Escherichia coli strains as isolated from fecal samples taken from 5-day-old calves that had not been offered antibacterial means. The resistance manifested was compared to that of E. coli organisms isolated from calves that had been given antibacterial agents in the course of 36 months as well as to the resistance of E. coli strains isolated from calves at 1, 3, and 5 months of age and from dam cows in the last 12 months of the experiment. A varying period was established for receding of the signs of resistance of the strains to antibiotics--6 months for E. coli to kanamycin and furazolidone, 9 months to tetracycline, chloramphenicol, and gentamycin, and 15 months to streptomycin. Strains isolated from newborn calves on farms with no records of infection were shown to be susceptible to all antibiotics, while those isolated from calves on farms where enteritis was recorded remained polyresistant up to 36 months. No correlation was found between the antibiotic resistance of fecal E. coli strains from the dams and their calves.

Experiments were carried out for the cultivation and indication of the swine pestivirus in several continuous and in primary cell lines, using lapinized and field strains of the virus. It was demonstrated that in the various cell cultures the strains used showed varying rates of growth. In PK-15 and pig embryonic kidney cell lines, the field strains and the virulent Vratsa strain replicated with no preliminary adaptation, forming numerous large fluorescent plaques at the 16th to 18th hour. In the same cultures the lapinized strains K and Hudson had more delayed growth, forming double plaques not until the 36th hour. In rabbit kidney primary cultures the virulent K strain only exhibited growth, and up to the 4th hour at that. All results obtained were in agreement with the results from biologic experiments with pigs and rabbits. Experiments were also carried out for the indication of the swine pestivirus in infected lamellae of the cell cultures used, which were subject to additional treatment for 5 min following primary handling with the specific marked serum with the 1:40,000 solution of Evans blue. The infected cells treated by this method showed light green fluorescence of the protoplasm, with a dark nucleus, while the intact cells had tile-red cytoplasm.