Risk of radiation exposure to medical staff involved in interventional endourology.

The aim is to estimate the possibility the new annual dose limit for eye lens to be exceeded and to study the impact of protective shield. Radiation exposure to medical personnel was evaluated with EDD-30 dosemeter in positions of operating surgeon, assisting doctor and nurse. At the operator's typical position for diagnosis and treatment of the urinary tract, the lens dose rates were 0.9 mSv h(-1) and 0.06 mSv h(-1) without and with lead shield. At the operator's position typical for percutaneous intervention dose rates were 1.9 and 0.02 mSv h(-1), respectively. At typical workload, the annual eye lens dose to the main operator without protective screen was estimated to be 29 mSv. With lead screen, operator lens dose can be reduced by a factor of 15-95 according to the procedure. Installation and use of lead screen and use of lead glasses were recommended to the endourology medical team.

[Experiments to identify Mycoplasma isolates from cell cultures]. / Opiti za identifitsirane na mikoplazmeni izolati ot kletuchni kulturi.

Identified were various species of Mycoplasma organisms isolated from three continuous cell lines--BHK-21, SPZF, and TT. On the base of cultural, biochemical, and serological investigations the isolates were defined as M. bovirhinis, M. arginini, and A. laidlawii. The bovine sera, used to culture the cell lines were shown to be the basic source of contamination with Mycoplasma organisms. This made it necessary to carry out a preliminary study on each batch of serum for Mycoplasma contamination prior to its use for laboratory and productional needs.

[Rapid peroxidase test for demonstrating the bovine pestivirus in cell cultures]. / Burz peroksidazen test za indikatsiia na govezhdiia pestivirus v kletuchni kulturi.

Different variants were tested of the immunoperoxidase method for the demonstration of the mucous disease-virus diarrhoea agent in infected cells with the use of a specific conjugated antiserum. It was found that the virus could be specifically demonstrated in infected cell cultures. The test proved rapid and readily applicable.

[Experiments to culture the bovine pestivirus in heterologous cell cultures]. / Opiti za kultivirane na govezhdiia pestivirus v kheterolozhni kletuchni kulturi.

Attempts were made to adapt a strain of the bovine pestivirus to cell cultures of swine kidney in a series of 15 passages. The adaptation of the virus was followed up through the production of a cytopathic effect, through comparative investigations, and by means of cytologic preparations. It was found that the cytopathic effect induced and the titer of the virus grew with increasing the number of the serial passages. Immunofluorescence and cytologic data showed the progressive development of the virus in cell cultures of swine kidney. It was also established that the time of incubation of the infected cultures to produce an overall cytopathic effect was shorter.

[Immunofluorescence demonstration of bovine pestivirus]. / Imunofluorestsentno dokazvane na govezhdiia pestivirus.

A high-titer hiperimmune calf serum was obtained via the manifold hyperimmunization with local strains of the bovine pestivirus, cultivated in homologous cell cultures. Its globulin fractions were treated with fluorescein isothiocyanate to produce a specific conjugate. The specificity of the immunofluorescent serum was demonstrated through the comparative study of cell cultures infected with various viruses. The method worked out was employed to investigate tissue cross sections from diseased calves, whereupon the opportunity for the rapid and specific diagnosis of mucous disease was demonstrated. The replication dynamic of a bovine pestivirus strain in cell cultures was followed up.

[A method for demonstrating mycoplasmas]. / Metod za dokazvane na mikoplazmi.

Bisbenzimid-marked continuous cell lines were investigated via fluorescent microscopy. The presence of Mycoplasma DNA was demonstrated in the cytoplasm with some of them. The method employed for the demonstration of Mycoplasma contamination is readily applicable, and could be used for control on continuous cell lines.

[Cultivation of bovine pestivirus in organ culture]. / Kultivirane na govezhdiia pestivirus v organni kulturi.

Attempts were made to culture strains of the bovine pestivirus in organ cultures of tracheal rings. Contrary to other scientists the authors used roller organ cultures of calf tracheal rings. The development of the virus in the cultures was judged by its presence in the maintaining medium through ELISA or by titration in cell cultures of fetal calf kidney. It was found that the two strains tested could be replicated in organ cultures of calf trachea, the intensity of multiplication being strongest between the third and the sixth day as demonstrated by ELISA. It was also established that the various batches of tracheal tissue had varying susceptibility.

[Immunofluorescent diagnosis of rota-, corona- and pestivirus infections in calves]. / Immunofluorestsentna diagnostika na rota-, korona- i pestivirusni infektsii po teletata.

Bovine hyperimmune fluorescent sera were obtained for indication of the rota- and corona-virus infections in calves, which were highly specific and of immunofluorescent titers within the 1:32-64 range. Their testing was carried out via the direct immunofluorescence method, using histologic cross-sectioned material and impression preparations of the mucous membrane of calves died of enteritis as well as cell cultures of fetal calf kidney and organic cultures of calf trachea all contaminated, resp., infected with feces. The study of the intestinal membrane of a total of 100 diseased calves, employing this method, has demonstrated a rotavirus antigen in 38.0 per cent of the cases, and a coronavirus one--in 37.0 per cent. The causative agent of mucous disease (a pestivirus) was demonstrated by means of the respective conjugate in 47.3 per cent of the cases, using abomasal membrane of a total of 55 calves. Rota- and corona-virus infections were also established in the abomasal membrane of diseased calves, and pesti-virus infections--in the intestinal mucosa as well. Established were also mixed infections with the three viruses taking part at various combinations. A celloidin method was worked out for making immunofluorescent preparations of infected monolayer cell cultures. In the cell cultures infected with feces the totavirus antigen was demonstrated in 19.4 per cent of the cases, and the coronavirus one--in 25.6 per cent.

[Kinetic study of the multiplication of the mucosal disease--viral diarrhea virus in homologous cell cultures]. / Prouchvane kinetikata na razmnozhavane na virusa na mukoznata bolest-virusna diariia v khomolozhni kletuchni kulturi.

Comparative studies were carried out on two local cytopathic strains of the virus of mucous disease-viral diarrhoea in primary cell cultures of fetal calf kidney and cell cultures of normal calf kidney in order to ascertain the yield of the virus and the development of a cytopathic effect. It was found that the amount of virus of the strain with strongly manifested cytopathic effect was directly proportional to its activity in the cell cultures of fetal calf kidney. Highest titers of the virus were obtained at the time of full cytopathic effect. In the same cultures the yield of the virus strain with less strongly manifested cytopathic effect was highest prior to the time of its fullest. The kinetics of propagation of the two viruses when culturing in such media proved to be similar to that when normal calf kidney cultures were used, however, the titers of the virus were lower by 1-2 logarithms. Both freezing and thawing of viral suspensions were found to contribute to the release of the virus from the incompletely destroyed cells. The yield of the virus in such cases rose only with the strain with a weak cytopathic effect if the procedure was carried out prior to its full manifestation.

[Adaptation of attenuated strain of P. parainfluenzae-3 in cultured swine kidney cells and analysis of its immunogenicity]. / Adaptirane na atenuiran shcham na P. parainfluenza-3 vurkhu kletuchni kulturi ot svinski bubrek i prouchvane na imunogennostta mu.

Strain Mihailovgrad of P. parainfluenza-3 was successfully adapted to cell cultures of pig kidney at its 15th passage. Its testing for innocuity was carried out through the inoculation of test calves with high amounts of the pathogen. No pathologic, temperature, and anaphylactic reactions were established. This confirmed the harmless character of the attenuated strain. Comparative testing for immunogenicity was performed with 8-month-old calves. Full coincidence with the antibody response was obtained with strain Mihailovgrad as a vaccinal strain. The use of the adapted strain for the production of a vaccine is to be preferred as there is no possibility of contamination with other bovine viruses.

[Serological study of the bovine virus diarrhea-mucosal disease]. / Serologichni prouchvaniia na virusa na mukozna bolest-virusna diariia po govedata.

Employed were the virus-neutralization test (VNT), the complement-fixation tests (CFT), and the immunodiffusion test (IT) in the study of serum samples of calves on a total of 25 farms that had records of virus diarrhea-mucosal disease (VD-MD) in the course of two years. Samples were also taken from calves in the initial phase of the same disease in the course of four months. The blood of experimentally infected calves waw likewise sampled for three months. It was found that the stage of infection could successfully be studied via all three serologic methods. Thus, for example, positive VNT and CFT results coupled with negative IT results spoke of the initial stage of the disease, and vice versa--negative CFT results and positive VNT and IT results gave evidence of the advanced stage of the infection.

[Comparative studies of plaque formation by strains of the mucosal disease-viral diarrhea virus (MD-VD)]. / Sravnitelni izsledvaniia vurkhu plakoobrazuvaneto na shtamove na virusa na mukoznata bolest-virusna diareia (MB-VD).

Studied was the phenomenon of plaque forming with 2 local and 1 reference cytopathogenic strain of the MD-VD virus in cell cultures of calf kidney and testis. Studied was also the effect of trypsin in the preliminary treatment of the cell culture as well as the varying composition of the cover medium. The strains were found to form plaques that were varying in type and size. The ratio between the large and small plaques as well as the percent of plaques having unclear edges could serve as tentative strain features. It was established that at such experimental procedure the preliminary trypsin treatment of the cultures increased but slightly the plaque-forming capacity of the strains. The results obtained give grounds to the necessity of characterizing the vaccinal strains used through the type and ratio of the plaques formed.

[Complement fixation test act in the diagnosis of mucosal disease-virus diarrhea in cattle]. / Reaktsiia za svurzvane na komplementa pri diagnostikata na mukoznata bolest-virusna diariia, pri govedata.

Experiments were made to obtain a highly active antigen for the complement-fixation test, using purification and concentration with methyl alcohol in a cell culture suspension of the causative agent of mucous disease-virus diarrhea. It was established that the CF test was sufficiently rapid and specific in the diagnosis of the disease in cattle. It proved instrumental in detecting complement-fixing antibodies in diseased and survived cattle, in calves with a latent infection and in cows with abortions.

[Combined prevention of viral infections in cattle]. / Kompleksna profilaktika sreshtu niakoi virusni infektsii po govedata.

On the basis of clinical observations and serological investigations a mixed type of virus infection of MD-VD parainfluenza-3 and adenovirus I was established. A complex prophylaxy against the virus infections proved in 2,800 heads of cattle was carried out, also on 1,400 heads of growing animals at the age between 6 and 18 months, as well as on 2,777 calves at the age of 6 months. The results of the immunoprophylactic actions showed the leading role of MD-VD in a virus infection. Owing to the steps taken the respiratory syndrome in the calves and in the cows was suspended. The falling away of calves was reduced from 15.4% to 3.2%, and the average daily growth was increased from 220 to 470 grams.

[Serological studies of the dissemination of neutralizing antibodies against the mucosal disease-viral diarrhea virus in cattle]. / Serologichni prouchvaniia za razprostranenie na neutralizirashti antitela sreshtu virusa na mukoznata bolest-virusna diariia; pri govedata.

During a serological study of 56 samples from cows, taken from prosperous farms, were proved in 37.5% neutralizing antibodies against the MD-VD, whereas the study of 89 samples from cows, taken from failing farms, the neutralizing antibodies against the same virus were 50.3%. Out of the 145 serum samples from calves, originating from prosperous farms 30.5% proved positive for neutralizing antibodies against the MD virus. Out of the 151 samples from calves, originating from failing farms, 65.7% proved positive. The data show the high degree of dissemination of the virus of that disease both on prosperous and on failing farms.

[Production and study of the immunogenic properties of a bivalent inactivated vaccine against mucosal disease (bovine viral diarrhea and infectious rhinotracheitis)]. / Poluchavane i prouchvane imunogennite kachestva na bivalentna inaktivirana vaksina protiv mukozna bolest (virusna diariia i zarazen rinotrakheit po govedata).

Bivalent inactivated vaccine against mucous disease (MD) and infectious rhinotracheitis (IR) in cattle was produced from cell cultural MD and IR virus suspensions. The vaccine was concentrated on aluminium hydroxide, inactivated by ethanol and is without residual virus. Saponine in final 1:1500 dilution is added as supplementary adjuvant. Immunogeneity of the vaccine was tested on 10-month-old calves, which had shown full resistance against experimental infection with virulent strains of both viruses. Testing on calves for harmlessness by use of a five-fold higher vaccine dose indicated complete tolerance of the vaccine. The prophylactic effect of the vaccine applied in practical work to directly threatened with immediate MD and IR infection cows, including pregnant ones, consisted in reduced number of cases of abortion, of inborn malformations, in lower neonatal calf death-rate, etc. No disturbances were observed following two-fold vaccination of the animals, a fact proving its harmlessness. The positive results of the studied vaccine allow its further application in the combined prophylaxis of MD and IR in calf fattening and breeding complexes.

[Trial of a hyperimmune serum against para-influenza 3, bovine adenovirus 1, infectious rhinotracheitis and mucosal disease]. / Izpitvane na khiperimunen serum protiv parainfluentsa-3, govezhdi adenovirus 1, zarazen rinotrakheit i mukozna bolest.

A four-valent serum was obtained by parallel hyperimmunization of cattle with live viral suspensions of parainfluenza-3, bovine adenovirus I, the virus of infectious rhinotracheitis and the mucous disease virus. The serum's neutralizing titres are between 1:1280 and 1:2560. The lasting exploitation of serum producing cattle indicates that no competition exists between the four antigens used in the process of hyperimmunization. Experimental testing of the serum on calves and its application in practical work proved its prophylactic and medicative effect. These results confirm the thesis that the use of passive immunoprophylaxis is needed in respiratory diseases of calves under conditions existing in intensive cattle-breeding.