Artificial feedforward as preparatory motor control in postictal hemiparesis.

One of the most important disturbances in spastic hemiparesis is the lack of reciprocal inhibition and the insufficient and inadequate preparatory programming of this inhibition. In 40 patients with postical hemiparesis some preparatory procedures foregoing the volitional movement attempt were assumed. The movement was extension of the wrist and the intended reciprocal inhibition was that in the wrist flexors. The procedures were extensor muscle vibration or electrostimulation which produce contraction of the wrist extensors and reciprocal inhibition in the wrist flexors. A conditioning has been attempted of these effects achieved at spinal level to the existing ipsilateral and spared contralateral cortical influences during a volitional extension of the wrist. In this way an artificial feedforward have been created, with favourable results in motor reeducation of wrist movements.

[Cultivation and study of the properties of the Perego strain of the sheep poxvirus on heterologous tissue]. / Kultivirane i prouchvane kachestvata na virusa na sharkata po ovtsete shtam Perego v kheterolozhna tukan

Strain Perego of the sheep pox virus, after 11 passages in lamb testis cultures, was successfully adapted and cultivated in 10 successive passages in a heterologous tissue--secondary cultures of newborn calf kidney. The infected cultures produced a cytopathic effect similar to that observed in a homologous culture, the difference being that part of the degenerated cells came off from the wall of the flask. At the level of its 10th passage the virus exhibited a titer of 10(3)CPE50. The virus was tested for harmlessness on sheep through a subcutaneous inoculation at a dose of 1 cm3 of a 1:10 dilution, and its testing for activity (1:100 dilution) caused an easily tolerated local reaction with a slight rise in the body temperature, the general status of the test animals remaining unaffected.

[Isolation of an adequate antigen for the diagnosis of enzootic leukemia in cattle with the agar gel immunodiffusion test]. / Poluchavane na pulnotsenen antigen za diagnostika na enzootichna levkoza u govedata s AGID-test.

An effective antigen was obtained, presenting a leukosis virus. The culture liquid, and occasionally the cells of the FIK cell line permanently infected with the agent of bovine leukosis served as a source of virus. The antigen, possessing a very good activity was produced by means of precipitation of the virus with 30 per cent ammonium sulfate, dialysis, and additional, concentration with polyethylene glycol-4000 until a 100-fold concentrations as against the initial volume of the virus was attained. Diluted antigen at 1:1 and 1:5 and leukosis serum produced in agar gel a precipitation line for 24 to 48 hours. In terms of activity and specificity this line did not differ from the line formed by glucoprotein antigens obtained from West Germany and the United States. With a normal bovine serum and sera containing Rota, and Parainfluenza-3 antibodies no precipitation line was formed. The good properties of the antigen were confirmed by joint investigations of bovine sera in this country and the Soviet Union with identical results. A total of 26 000 sera were examined with the newly obtained full value antigen, establishing the spread of the leukosis infection in this country as well as the fact that it had been imported from abroad.

[Diagnosis of transmissible gastroenteritis in swine by the agar gel immunodiffusion test]. / Diagnostika na transmisivniia gastroenterit po svinete s AGID-test.

A transmissive gastroenteritis antigen was obtained from intestinal content of pigs with symptoms of the disease, the presence of which was demonstrated by the agar gel immunodiffusion test. It was shown that the antigen was rough and lacking in purity, but it proved to be sensitive and specific. In the conditions of agar gel immunodiffusion in the presence of a reconvalescent serum the antigen produced a clearly expressed precipitation line for 24 to 48 hours. A correlation was also found with 17 out of 25 reconvalescent sera of pigs, investigated via virus-neutralization and agar gel immunodiffusion. Four sera were positive through virus-neutralization only, and four--through agar gel immunodiffusion, while the controls were negative. The agar gel immunodiffusion test was useful in the demonstration of both antibodies in reconvalescent sera and virus in the intestinal content of pigs either suffering or died of transmissive gastroenteritis.

[Differentiation of strains of the swine fever virus depending on their temperature resistance at 56 degrees C and on the size of fluorescent plaques]. / Diferentsirane na shtamove ot virusa na chumata po svinete v zavisimost ot rezistentnistta im na temperatura pri 56 gradusa C i goleminata na fluorestsirashtite plaki.

In vitro and in vivo experiments were carried out to differentiate the virulent swine fever virus strain Vratsa and the vaccinal strains K and VP with regard to their resistance at 56 degrees C and to the size of the fluorescent plaques. The results obtained were comparable. The virulent strain was found to retain its viability at temperature of 56 degrees C for 30 min. The heated virus formed large, strongly fluorescent plaques in the infected cell cultures of pig kidney. The fluorescent cells were enlarged, and their cytoplasm was granular. The treated virus retained its pathogenic properties. Pigs inoculated with the inactivated Vratsa strain contracted the disease and died. Prior to heating the vaccinal strains formed small fluorescent plaques in cell cultures. The fluorescent cells had normal size and homogenic structure. Following heating at 56 degrees C for 15 min the vaccinal viruses retained partially their viability. Thus inactivated the viruses formed a limited number of fluorescent plaques of low intensity.

[Adaptation and cultivation of the Perego strain of ovine smallpox virus in tissue culture and an evaluation of its immunogenic properties]. / Adaptirane i kultivirane virusa na sharkata po ovtsete shtam Perego v tukanni kulturi i pretsenka na imunogennite mu kachestva

The strain Perego of the sheep pox virus, used for the production of the ovinized vaccine in this country, was adapted and cultured in tissue cultures of lamb testes. A total of ten passages in succession of the virus were performed with the manifestation of a characteristic cytopathic effect in the cultures. The titer of the virus was found to be within the range of 10(3.5)CPE50, for the initial passages, to 10(4.5)CPE50, for the final passages. The activity and harmlessness of the virus was tested on sheep. The inoculated 14 sheep with one vaccinal dose each, containing 100 CPE50, and two sheep treated with tenfold higher dose of the virus showed that sheep in general tolerate well the rates at which the virus was applied within the range cited. The general state of the sheep did not exhibit deviations, however, the animals' body temperature rose, and there were reactions at the site of the inoculation. Serum-neutralizing antibodies were established in the blood of sheep one month following vaccination.

[Determination of the leukemia virus in the lymphocytes of sick cattle]. / Ustanoviavane virusa na levkozata v limfotsiti na bolni goveda.

Experiments were carried out to establish the leukosis virus in lymphocytes from the peripheral blood of spontaneously infected cattle. The infected animals were detected by means of the agar gel immunodiffusion test in demonstrating the presence of leukosis virus antibodies. Lymphocytes were obtained from the blood of positively reacting animals, which were cultured at 37 degrees C for 3 to 5 days in a 'MEM' nutrient medium with the addition of 10 per cent fetal calf serum and antibiotics. The virus in the cell culture liquid was concentrated with ammonium sulphate and polyethylene glycol after which it was tested for antigenic properties. Parallel to this the lymphocytes were studied via the electron microscope prior to and after culturing. It was found that at culturing such lymphocytes the culture liquid contained the virus, which, after concentration exhibited antigenic properties in the agar gel immunodiffusion test, forming a precipitation line with a leukosis-positive serum. As found by the electron microscope there were in the lymphocytes prior to and after cultivation viral particles which proved similar to the leukotic 'C' type viruses with budding of the cell membrane that was characteristic of the bovine leukosis virus.

[Use of cell agglutination with concanavalin A to detect cattle infected with the leukemia virus]. / Izpolzuvane na kletüchnata aglutinatsiia s konkanavalin A za otkrivane na goveda, infektirani s virusa na levkozata.

The method of cell agglutination with concanavalin 'A' was employed to study lymphocytes from the peripheral blood of cattle spontaneously infected with the virus of leukosis. The infection in the animals was demonstrated through the agar gel immunodiffusion test based on the presence of antibodies. As controls served lymphocytes of normal cattle that were serologically and clinically negative for leukosis as well as lymphocytes, of cattle that were immunized with the virus of the mucous disease and with adeno-, rota, and parainfluenza-3 viruses. It was found that 10(6) lymphocytes of cattle infected with the leukosis virus was agglutinated by concanavalin 'A' used at the rate of 500-2000 microgram/cm3, while the same amount of lymphocytes of normal animals or animals that were immunized against the other viruses got agglutinated by concanavalin 'A' at 4000-8000 g/cm3.

[Comparative studies of sera from cattle with complete leukemia virus and glycoprotein antigens]. / Sravnitelni izsledvaniia na serumi ot goveda s antigeni ot polnotsenen levkozen virus i gliukoproteini.

One hundred cattle serums were investigated by the AGTD-test with two antigens: an antigen produced by the whole virus and an antigen containing glycoproteins. Of all serums studied 44 showed a specific precipitation in case the glycoprotein antigen was used. In case the antigen from the whole virus was used 41 serums showed a specific precipitation line, while in 3 of the serums two precipitation lines were observed. Fifty six serums proved negative, containing no antibodies against bovine leucosis virus, after antigens were used. In 2 of the serums non specific precipitation lines were obtained when the antigen from whole virus was used. the precipitation lines produced by both antigenes did not differ in intensity and time of manifestation.

[Serological diagnosis of bovine leukosis using the agar gel diffusion test]. / Serologichna diagnoza na levkozata po govedata s pomoshtta na agar gel difuzionnata proba.

Experiments were carried out to use the agar gel diffusion test (AGDT) in the study of bovine leukosis. An antigen was obtained from FLK-24 cells with a latent leukosis virus infection, which proved specific and suitable for AGDT. A total of 134 serum samples were examined applyig AGDT, for the presence of specific antibodies, originating from cattle of herds in which leukosis had been hematologically demonstrated. Investigated were also 56 sera of animals presenting an unknown clinical picture. Positive reaction was established in 70 per cent of the sera taken from herds with hematologically demonstrated leukosis. The specificity of AGDT was confirmed through establishing specific antibodies also in sera of lambs experimentally infected with a virus from a FBL-J 5 cell line with a latent infection. It is admitted that AGDT is a specific, sensitive, and readily applicable method, which can successfully be used in the diagnostics of leukosis in this country.

[Leukemia in sheep on a state farm]. / Prouchvane na levkoza po ovtsete v edna obshtestvena ferma.

Leukosis was diagnosed in a flock of sheep. It was studied epizootiologically, clinically, morphologically, virologically, and serologically in the course of two years. Fifteen sheep manifested clinical symptoms of the disease. Involved were the lymph nodes (superficial, skeletal, and visceral), liver, spleen, heart, and kidneys. Histologically, there were diffuse or limited lymphoid cell proliferations, some of them showing small unreactive cell elements. Sixty-two out of 160 serologically studied sheep showed in their sera antibodies against the virus of bovine leukosis as established by means of the agglutination immunodiffusion test. The leukosis virus was obtained from lymphocyte cultures isolated from infected sheep. It was used in the production of an antigen. A specific precipitation line was produced in the interaction between the sheep leukotic antigen and the bovine leukotic serum in the agglutination immunodiffusion test. Such data spoke of the antigenic similarity between the virus isolated from leukotic sheep and the virus isolated from leukotic cattle. The slaughterhouse inspection of 157 clinically normal sheep revealed tumoral lesions in 4 more animals. The changes were seen in the lymph nodes. No such changes were observed in the parenchymal organs.

[The spread of enzootic bovine leukemia via the seminal fluid in certain breeds of bulls]. / Razprostranenie na enzootichnata levkoza po govedata sus semennata technost ot niakoi porodi bitsi.

Studied was the occurrence of enzootic bovine leukosis as dependent on the use of semen of leukosis-affected bulls for the artificial insemination of cows and heifers and their offsprings in the F1 generation on 16 farms. Semen was used of a total of 30 bulls of the Holstein-Friesian, American Brown, and European Black-and-white breeds. The agar gel immuno-diffusion test was employed to establish antibodies to the bovine leukosis virus in the sera of the bulls. On 9 farms with 2,997 cows and heifers that were negative for leukosis antibodies a total of 800 female calves (F1) were born. Serologic investigations of both dams and calves, aged 2 to 5 years revealed no leukosis antibodies. On other 7 farms with 1,717 cows and heifers, among which sporadic carriers of BLV-antibodies were discovered, 713 female offsprings (F1) were born. Seventeen (2.38 per cent) out of these responded positively for BLV antibodies. Twenty-two (3.0 percent) of the dams following calving also showed a positive reaction. Over the 1981-1985 period a total of 1,593 female calves were born as the offsprings of 4,714 cattle on all 16 farms. The percent of the positively responding to leukosis was 1.06, resp., 1.38. These results were considered indicative in ruling out the transmission of enzootic bovine leukosis with semen in the artificial insemination of cows and their F1 offsprings.