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One of the practical applications of flow cytometry is the possibility of the analysis of leukocyte populations which participate in immunological phenomena in ruminant mammary glands. By use of the flow cytometry method the investigations can be conducted in a quick, precise and highly repeatable manner. Not only the quantitative assessment of immune cells present in milk is possible, but also the assessment of their qualitative variety and particular subpopulation affiliations. The differences in specific subpopulations content which are present in mammary glands in distinct physiological conditions (lactation and dry period) enable a quick and precise evaluation of immunological status and the recognition of mechanisms which take part in the immune resistance of the gland. With flow cytometry analysis of leukocyte surface antigens, apoptosis and phagocytosis, it is possible to understand the function of immune cells and immunological phenomena in mammary glands in conditions of health and disease. Flow cytometry could be successfully applied for monitoring the intensity of inflammation processes during the course of mastitis and causal and symptomatic therapy effectiveness assessment. Thus it creates new possibilities for developing more efficient treatment and prevention strategies for mastitis, which is of great significance in the dairy industry because of the possibility of preventing economic losses and increasing the safety of dairy products of animal origin.
The article presents basic principles of flow cytometry (FCM), which is a highly advanced technology based on measuring physical and chemical parameters such as: light scatter at different angles and fluorescence. The essential principle of flow cytometry is identifying cell surfaces and intracellular antigens using specific monoclonal antibodies conjugated with fluorochromes. Cells labeled with fluorochromes pass through the flow chamber and, when exposed to the laser beam, they emit and scatter light, causing alterations in the intensity of the light. Light scatter and fluorescence is measured at the same moment. Light signals are converted into digital signals by a photomultiplier system and analyzed by computer. Flow cytometer and computer software provide multiparameter qualitative and quantitative analysis of single cells in a quick, precise and repeatable manner.
The number of ways in which flow cytometry may be applied in veterinary sciences is continually increasing, especially in the fields of immunology, oncology, pharmacology and microbiology. White blood cell analysis by flow cytometry, and in particular, the study of leukocyte antigens, phagocytosis and intracellular killing, is being applied to an ever growing number of animal species. Moreover, flow cytometry enables red blood cell analysis, including reticulocyte count and maturity, identification of anti-erythrocyte antibodies and intraerythrocyte parasites detection. Through flow cytometry it is possible to make a speedy and precise diagnosis of neoplasms. In diseases of the haematopoietic system, such as leukemia and lymphomas this method allows the cell line which has become malignant to be precisely established. When appropriate procedures are used, solid tissues such as tumors can be investigated, and if there is no direct access to tumors, it is possible to study cells from secondary lesions - e.g. pleural fluid or peritoneal fluid. Flow cytometry can provide information about sperm parameters, such as sperm cell chromatin structures or differentiations between X and Y bearing sperm cells. The flow cytometry method enables a wide range of diseases to be diagnosed by studying apoptosis, i.e. programmed cell death. When adequate, modified procedures are applied, it can be utilized in diagnosing bacterial and viral infections and it is the only method which makes it possible to determine cytokines produced by different cell populations, and cytokine sets produced by a single cell.
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The aim of the study was to assess the effect of selected isolation methods on the viability and metabolism of bovine leukocytes. The cells were isolated using a Ficoll 1077, Histopaque 1083 gradient and osmotic shock method, and Ficoll or Histopaque with osmotic shock. Evaluation were made of the total number of cells, viability after isolation and in 24h culture on RPMI 1640 medium and metabolism with NBT reduction assay. Microscopic and cytometric evaluation of the leukocytes revealed that the isolation methods applied had an influence on their number and viability. Based on the results it can be concluded that isolation methods of cells in a Histopaque or Ficoll yield highly pure cell fractions with high viability.
Changes in selected blood lymphocyte subpopulations in dogs administered with a soluble parasitic antigen (SPA) derived from a supernatant of 18S RNA-A and 18S RNA-B Babesia canis cell culture were investigated. The studies included 20 dogs divided into three groups: group I (n=8) - comprised of dogs receiving SPA twice, at 3 week intervals; group II (n=5) - nonvaccinated control dogs, and group III (n=7) - dogs vaccinated twice with a commercial B. canis vaccine. Cytometric analysis revealed that vaccination with SPA derived from B. canis culture had similar effects to the vaccination with a commercial vaccine. The vaccination lowered the percentage of T lymphocytes (CD3+), T helper cells (CD4+), cytotoxic/supressor T cells (CD8+), B lymphocytes (CD21+), and MHC II lymphocytes in the blood in comparison to non-vaccinated dogs. Statistical analysis of the results demonstrated that mean values of the tested parameters at each stage of the study were similar in groups I and III and significantly higher in group II. The lowered level of the lymphocyte subpopulations in groups I and III persisted during the whole period of the study. The results presented that SPA has immunosuppressive effect in the first period after being administrated.
In sheep raised in chamber system and fed concentrate fodder containing high dose of zearalenone and its metabolite (α- zearalenol), the clinical course of zearalenonosis was diagnosed. Control animals were kept on grazing-land from the spring to the late autumn, and only in winter time they were fed shredded wheat with the lowest concentration of zearalenone. These sheep showed no clinical symptoms of the mycotoxicosis. Zearalenone and α-zearalenol cause immunosuppression, which means that lymphocyte T CD4+ and lymphocyte T CD8+ percentages decline and CD4/CD8 ratio increases when compared with control animals. Zearalenone mycotoxin suppression effect modulates cellular immunological response, which is essential in suppression of post-vaccination immunity and infectious diseases development despite applying normal specific immunoprophylaxis.
Expression of CD4, CD8, and CD25 surface markers on T lymphocytes and levels of IFNγ, IL-10, and TNF-α in colostrum and milk were determined in sows vaccinated against Trueperella pyogenes in the final stage of pregnancy. The autovaccine, prepared from Trueperella pyogenes, administered twice to pregnant sows six and three weeks before the anticipated delivery significantly increased the percentages of TCD4+, TCD8+, and TCD25+ as well as levels of IFNγ, TNF-α, and IL-10 in colostrum and milk. The enhanced immune potential of colostrum effectively protected the piglets against T. pyogenes infections during weaning and thus reduced the economic losses on the particular farm concerned, where T. pyogenes infections occur endemically. Knowledge of the profile of cellular and humoral immune response in colostrum and milk of vaccinated sows will enable the design of a T. pyogenes infection prophylactic programme for suckling pigs and weaners, which are most susceptible to infections.
The aim of the study was to assess bacteriolytic activity of lysozyme and serum amyloid A (SAA) level in sheep affected with zearalenone mycotoxicosis. Bacteriolytic activity of lysozyme, and serum amyloid A (SAA) level are both the elements of innate humoral immunity. Lysozyme bacteriolytic activity in serum was determined by diffusion-plate method with reference to Micrococcus luteus. SAA concentration was determined by the use of commercial ELISA kit (Phase Serum Amyloid A Assai TP802). The highest lysozyme bacteriolytic activity was observed in sheep with total rectal and intestinal mucosal membrane prolapse. Lysozyme concentration values in animals with partial rectal prolapse were significantly lower. In the control group, lysozyme concentration was low and within the range considered as physiologically normal. The highest levels of SAA, which ranged from 38.5 to 172 µg/mL, were detected in sheep in which the highest lysozyme bacteriolytic activity was noted. From the data obtained, it is undoubtful that changes in SAA level in affected sheep and control sheep are reliable indicators of zearalenone mycotoxicosis progress and termination. The highest levels of SAA were noted in animals, which had the total rectal and intestinal prolapse in course of zearalenone mycotoxicosis, and after returning the rectum to the normal position, mucosal membrane necrosis occurred, which resulted in perforation and peritoneum inflammation. The observed differences in SAA level forming range in particular animals from infected group are conditioned by the character of inflammation process and intensity in organs altered by the disease, which are principal factors inducing changes in its concentration. The level of this protein in serum reflects activation state of immunological system and could be one of the criterions in sheep health assessment.
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