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A simple and quick method of viral DNA purification from RK 13 infected with NIA-3 strain of ADV cell culture yielded DNA which was easily digested with its enzyme restriction. Moreover, it was of a sufficient purity for a restriction pattern (RFP) analysis. The purified DNA was labelled with photobiotin to obtain a biotinylated genetic probe. The full length DNA probe that was developed was found to be very sensitive and specific when it was used for hybridization with ADV DNA. Furthermore, the forenamed biotinylated probe greatly enhanced the detection limits of restriction fragments compared to RFP analysis in ethidium bromide stained agarose gel. These results indicate that the described probe can be used for analysis and characterization of ADV genomes even if only minute amounts of viral DNA are available.
The purpose of the survey was to assess the prevalence of BHV-1, PI-3, BHV-4, BRSV and BVD in the bovine respiratory tract. Sera were taken from cattle of four districts located in the south-western part of Poland: 349 sera were collected from cows, 183 from heifers and 27 from bulls with no clinical signs of the disease. The findings revealed higher indices of infection caused by the viruses in the group of cows as compared with the one of heifers, and the highest percentage of infections due to PI-3 virus in all groups of the animals. With respect to viruses and districts under study, the following indices of infections were found: BHV-1 from 6.2 to 44.4 per cent, PI-3 from 32.7 do 69 per cent, BHV-4 from 13.9 to 40 per cent, BRSV from 8.5 to 44.4 per cent and BVD from 8.5 to 27.7 per cent. The results indicate significant differences in respect to virus infections caused mainly by the home and international market of cattle. It is worth mentioning that mixed infections were observed more often than monoinfections.
The protein antigens of BLV were detected in the lysates of bovine lymphocytes stimulated in vitro using the Western blot method. Specific antibodies against BLV were detected in the sera of animals by the ELISA test. Protein bands of the molecular weight 72, 51, 35 and 24 kD were detected by the rabbit antiserum against BLV in the blots from infected lymphocytes and FLK cells. Thе proteins mentioned above were not detected in the lysates of lymphocytes of uninfected animals. Densitometry analysis of immunoblots from FLK cells indicated that a minimal amount of 100 ug of gp51 viral protein can be discovered. The presence of BLV antigens and specific antibodies were detected in 18 of 25 animals. The antibodies were also found in four cows of the remaining seven animals whose lymphocytes were free from BLV proteins.
With immunofluorescence techniques large foci are visible in frozen sections of the tonsils and spleen of pigs infected with virulent strains of HCV. Low or moderate-virulent strains induce small, weakly fluorescent foci under the same conditions. This sometimes causes diagnostic problems. Therefore, under such conditions, isolation of virus in cell cultures should be applied for HC diagnosis. The culture might be examined for the presence of HCV by direct IFT using immunoenzymatic methods (PLA). The usefulness of the PLA for the diagnosis of HC was compared with IFT. Forty samples of tonsils, spleens and kidneys were collected from 10 pigs experimentally infected and from 5 field cases of HC. Isolation was performed on rapidly growing PK-15 cells seeded in flat bottomed microtitre plates. The cultures after 48 h were fixed and stained with hiperimmune porcine HC antiserum and after that with anti-porcine IgG-HRPO conjugate. The results were read microscopically using 50 X magnification. The results were considered positive if stained reddish-brown infected cells were detected. The applied immunoenzymatic method enables the detection of HCV in all samples, from experimentally infected pigs and field cases of HC. Using IFT, in some cases, it was difficult to determine exactly the results of examination.
Using the PCR method the proviral sequence of the bovine leukaemia virus was detected in the peripheral blood leukocytes of cattle from an infected herd. BLV antibodies were determined by the ELISA and AGID tests. PCR amplification was performed with one set of 20-mer oli- gonucleotyde primers that should produce a 364 bp fragment of BLV-DNA located in the gag gene region. The reaction products were analyzed in 1 A°/< agarose, blatted to Hybond-N filter by the Southern method and probed with an 8.3 kb Sac I fragment of BLV, labelled with di- goxigenin -dVTP. In 23 animals examined by PCR the presence of proviral DNA was found in all serologically positive animals and also in three serologically negative animals. BLV-DNA was not detected in only one seropositive individual. The presented findings indicate that the determination of the proviral DNA of BLV using the PCR method is more sensitive than serological tests and it should be beneficial for the diagnosis of cattle infection with BLV.
Clinical signs, haematology (leucopenia, lymphopenia, neutropenia) and results at necropsy may only suggest a disease suspected of a parvovirus etiology. Real proof of this kind infection is based on identification of canine parvovirus in faeces of a sick dog. Because of the common occurence of CPV-2 infections in dogs there is need to introduce a rapid test which would make it possible to perform a proper diagnosis immediately after the collection of the samples of faeces in hospital. In this paper the presence of CPV-2 was demonstrated by means of the test developed by On-Site Biotech (Uppsala, Sweden) on 41 of 50 stool samples with clinical signs suggesting parvovirus disease. Of 41 infected dogs 40 were leucopenic (leucocytes ≤ 4.5 G/L), lymphopenic (lymphocytes ≤ 1.3 G/L) and neutropenic (neutrophiles ≤ 4.0 G/L). Of nine dogs uninfected with CPV-2, none showed leucopenia, lymphopenia or neutropenia.
The growth power of different cell lines: calf kidney, heart fibroblasts, thymus and foetal testicles, as well as porcine kidney in 17 types of media prepared on the basis of Hanks, Eagle’s and Parker’s media were studied. The conditions for the preparation of cell suspensions for deep freeze storage and the optimal conditions for cell growth after thawing were determined. The titers and intensity of CPE od FMD virus, type A, О and C, propagated in cell cultures obtained directly after trypsinization and after 6 months of storing the cells in liquid nitrogen (-196°C), were similar in calf kidney cells, pig kidney cells and calf thyroid cells. No cyto-pathic effects were observed in cultures of calf heart and foetal calf testicles infected with FMDV type A, О and C.
Pigs serve as major reservoirs of H1N1 and H3N2 influenza viruses which are endemic in pig populations worldwide and are responsible for one of the most prevalent respiratory diseases in pigs. Therefore the early detection and identification of such events are paramount in monitoring the spread of influenza viruses. Transfer of influenza A viruses from animal hosts to man may lead to the emergence of new human pandemic strains. The aim of the study was to prove the matrix gene useful for reverse transcription nested-PCR as sensitive and specific for the detection of swine influenza A viruses in clinical samples. 75 RNA-virus positive samples out of 235 samples, including nasal swabs, lung tissues and whole blood samples, were detected by RT-n-PCR. Using conventional virology method we isolated 33 SIV strains in embryonated chicken SPF eggs. The results of PCR were 100% in agreement with those of virus isolation. The limit of detection of SIV was 10-7 EID50/0.1 ml. These results demonstrate the usefulness of RT-n-PCR for the detection and identification of influenza A virus in clinical material.
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