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The experiments were carried out on 94 hamster females (765 live foetuses), 78 rats (724 foetuses) and 32 rabbits (237 foetuses). The commercial chlorfenvinphos (2-chloro-1-/2,4-dichlorphenyl/vinyl diethyl phosphate) and bromfenvinphos (2-bromo-1-/2-4-dichlorphenyl/vinyl diethyl phosphate) preparation were administered p.o., once or three times to pregnant animals in rape oil during the time of organogenesis. The animals were sacrificed two days before the term, and foetuses were examined according to experimental designs adopted for teratogenic studies. The results obtained indicate that bromfenvinphos possesses weaker embryotoxic properties than does chlorfenvinphos. No teratogenic action of bromfenvinphos for hamster and rat foetuses has been found while chlorfenvinphos induced sporadic developmental abnormalities in hamster and rabbit foetuses.
Разработали метод намножения вакцинарного вируса болезни Ауески на куриных фибропластах с применением ферментора отечественного производства, заменяя применяемые до сих пор колбы Ру. Привели основные параметры намножения вируса в ферменторе. Сравнительные исследования (в глубинной и стационарной культуре) показывают, что намножение вируса в глубинной культуре происходит исправнее, без понижения иммуногенной ценности антигена. Антиген, полученный 2 методами, применили для изготовления вакцин, похожим образом предохранявших иммунизируемых животных.
Medycyna Weterynaryjna
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2010
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tom 66
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nr 07
s.475-479,tab.,bibliogr.
Varroasis has been treated with numerous different substances, including amitraz, which has been used since 1981. In 1984, Apiwarol AS - a drug in the form of a flammable tablet containing 12.5 mg of amitraz - was registered. The active substance, diffusing with smoke particles into the beehive, paralyzes Varroa destructor within an hour. Amitraz is also used as a component of other drugs, e.g. Biowar, which has the form of plastic strips containing 400 mg of the active substance. Unlike in the case of Apiwarol AS, amitraz diffuses slowly, reaching a therapeutic level in the beehive in 6-8 weeks. Over 25 years of observation on the combating of varroasis indicate that the parasites may develop resistance against amitraz, which has usually been observed after treatment with strips. Presumably, a long exposure to the substance released from the strip is more likely to produce resistance than fumigation with Apiwarol AS over a relatively short time. However, some reports of a reduced efficacy of fumigations have also been made. In these cases the efficacy of the drug may have been reduced by such factors as inappropriate application; season of the year and time of the day when the drug was used as well as the number of fumigations. On the other hand, a comparison of results for the years 1981-1985, 1986-2000 and 2001-2009, presented in numerous studies, indicates that there were no statistically significant (P ≤ 0.05) differences in the efficacy of combating V. destructor with amitraz in these periods, which was 93.6 ± 3.73%, 95.4 ± 3.43% and 93.2 ± 6.59%, respectively. Nevertheless, further laboratory and field investigations are required to assess the ability of the parasite to develop resistance against Apiwarol AS.
The attenuated classical swine fever virus (CSFV) strain has been chosen for adaptation cf CSFV to tissue culture. The PK-15A line of pig kindney cell culture was used for multiplication of the vaccine virus. The cell line was cultivated according to generally accepted methods with addition of 5% calf serum absolutely free from antibodies to BVDV. The titre of noncythopatic vaccine CSFV was determined by the Peroxidase Linked Antibody Assay (PLA) and it amounted to 10⁴‧⁵ ТСID₅₀. The best parameters for multiplication of the chosen virus strain were determined with relation to the stationary and roller cultures. The highest titre of vaccine virus 10⁸‧⁰⁰ TCID₅₀ was obtained by infection of fershly trypsinized cells in Legroux flask with a dose of 10⁵ TCID₅₀ and their incubation at 37°C for 96 hours. Infection of the roller culture of PK-15A cell line with the same virus dose resulted in a titre of TCID₅₀ = 10⁸‧⁷⁵. Taking into consideration these results, 6 batches of attenuated tissue vaccine against CSF were prepared in the roller culture of PK-15A cell line. It has been shown that new attenuated „Cellpest” vaccine against CSF, produced in roller culture of PK-15A cell line, has the same properties of safety and immunogenicity as lapinized vaccine.
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