Thrombophilia screening in young patients with cryptogenic stroke. Prevalence of gene polymorphisms compared to healthy blood donors and impact on secondary stroke prevention.

UNLABELLED: The clinical relevance of thrombophilia screening in stroke patients is still a matter of debate, and descriptions of larger patterns of genetic variability are rare. We assessed the frequency of hereditary hypercoagulability in young patients with cryptogenic stroke (n = 44) and in healthy blood donors (n = 282) without prior cardiovascular event. Furthermore, we focused on the impact of thrombophilia screening on secondary stroke prevention. RESULTS: Compared to the control group (19-67 years; median 38.5 years; 64% women), there was a lower prevalence of the FVII-R353Q mutation (p = 0.033) in stroke patients (17-52 years; median 36 years; 59.1% women). Of note, the FVII-R353Q mutation lowers FVII plasma levels, probably reducing the risk of cardiovascular events. The prevalence of the remaining 13 gene polymorphisms did not differ significantly. However, the prevalence of FV Leiden mutation tended to be higher among stroke patients. CONCLUSION: Overall, extended screening for inherited thrombophilia had an impact on medical stroke prevention in every sixth patient with cryptogenic stroke.

[Extraction and freeze-drying of herpes virus C3-1 isolated from turkeys]. / Ekstrahirane i liofilizirane na kherpesen virus shcham C3-1, izoliran ot puiki.

Possibilities for producing dried preparations of turkey herpes virus C3-1 by use of various ultra-sound desintegrator-systems and different ways of processing the cell suspensions containing the virus were studied. It was established that cell-less virus of a 1.5 to 2 log smaller quantity than the initial virus containing cell suspension can be produced by ultrasound generator with an indirect action -- a vibrating membrane, which transmits the impulses through a liquid medium and the container's walls on the object. The use of a generator with direct action -- titanic probe placed into the suspension results in an insignificant loss and in some cases even leads to higher titer. In the process of freeze drying the protective media SPGA, 5% pepton and 5% horse serum produce almost equal results. Highest dried virus yield was produced by lyophilization of entire (without centrifugal separation) ultrasounded cell suspension. In such cases the titer of the freeze-drying virus was by 0.2-0.4 log higher than the initial cell virus determined after the microplate method. The authors are of the opinion that titration by this method does not give an exact criterion for comparison of virus content in frozen cell and freeze-dried preparations. A proper protection against Marek's disease was established in laboratory and terrain experiments with chickens following immunization by freze-dried preparations of the strain C3-1 (losses were reduced 3-4 times). An immunization dose of 2000 POU lyophilized virus is recommended for practical use.

[Isolation of an avirulent strain of the chicken herpes virus type B]. / Izolirane ne avirulenten shtam kokoshi kherpesvirus tip B.

Experiments were carried out to isolate type 'B' of the chicken Herpes virus on a farm for stock layers with a low level of losses due to Marek's disease. Seven virus isolates were obtained from 3-4-month-old White Leghorn poults via direct kidney cell cultures. One of them, named strain C-80, was studied in chick embryo fibroblast cultures, and egg cultures (Büllow's test) as well as biochemically, serologically, and through the electron microscope. Results made it reasonable to identify it as a chicken Herpes virus type 'B'. In vivo experiments with strain C-80 inoculated in day-old chicks at the rate of 15 x 10(3) PFU showed that it did not cause gross and microlesions in the nervous system and the parenchymal organs in the course of 18 weeks of observation. The immunogenic properties of strain C-80 were studied in 2250 day-old White Plymouth Rock chicks inoculated at the rate of 1360 PFU, kept in an infected environment together with as many as 4500 control birds immunized three times with a vaccine (obtained from a turkey Herpes virus) at 1500 PFU. Twenty-four weeks later the losses due to Marek's disease were 3.4 per cent in the test group, and 7.2 per cent in the control one. It is believed that strain C-80 is appropriate for the production of a vaccine against Marek's diseases--Rispens type. Further studies are being performed on the antigenic composition and the immunogenic properties as well as series of in vivo passages with regard to reversibility.

[Obtaining a specific antigen for the comparative testing of immunological methods in the diagnosis of Marek's disease]. / Poluchavane na spetsifichen antigen za sravnitelno izpitvane na niakoi imunologichni metodi za diagnostika na bolestta na Marek.

Comparative studies were carried out on the diagnostic possibilities of immunological methods--precipitation in agar gel, immunofluorescence and indirect hemagglutination, as well as isolation of the virus through primary cellular cultures for the diagnosis of Marek's disease. For the purpose were obtained 9 series of specific antigens. The comparative studies were carried out on fowl and blood serums from different poultry yards, as well as from SPF chickens, experimentally infected with HPRS-16 strain. The results obtained justify a precipitation in agar gels as the most convenient for mass diagnosis of Marek's disease.

[Enzootic dermonecrosis in chickens]. / Enzootichna dermonekroza po kokoshkite

An enzootic of necrotic dermatosis in hen layers was described. The changes consisted in that they had constant localization and demarkated sites on the skin between the back and the neck. The disease was observed on a farm for 5000 layers in the course of two consecutive years. All birds contracted the disease and in the first year they recovered the 10 months; in second year they recovered for three months. Each bird showed symptoms for 3 weeks. The skin lesions resulted in cicatrization. The etiologic agent (a Pasteurella-like organism) was isolated from the necrotic foci. It proved pathogenic for albino mice and manifested biochemical activity and morphology characteristic of Pasteurella multocida. The disease was successfully reproduced with a broth culture applied on a scarified skin of test birds. Histopathologically, the spontaneous lesions proved undistinguishable from the experimental ones and represented coagulation necrosis of the epidermis, derm, and subcutis. It is supposed that the constant localization was due to the porte d'entrer of the infection, associated with the bad habit of picage on the neck as demonstrated on a large scale by the birds of the infected flock. This is characteristic of some lines of the White Leghorn breed.

[Effectiveness of a Bulgarian vaccine against Marek's disease in broilers]. / Efektivnost na bulgarskata vaksina protiv bolestta na Marek pri broileri

Studies were carried out to establish the effectiveness of the immunization of broilers against Marek's disease using a Bulgarian vaccine produced with strain C3-1 of a turkey herpes virus. The experiments were done under the conditions of an industrial poultry dressing combine with a total of 52,450 day-old hybrid birds vaccinated at the rate of 1000 plaque-forming units (PFU), 39,450 birds vaccinated with 500 PFU each, and 91,564 unvaccinated control birds. After the 60-63-day fattening period was over the average value of the mortality rate was 2.17 per cent and 2.48 per cent in the vaccinated birds and the controls, respectively. The vaccinated groups of birds showed also a comparatively higher weight gain--by 73 g, on an average, recorded prior to slaughter--as against the control groups. No differences were found in these indices between the groups immunized with 1000 and 500 PFU. In a laboratory test with 255 birds divided into four groups immunized with 100, 500, 250, PFU and controls, challenged in the third week with a pathogenic herpes virus it was found that up to the 6th month the first two groups developed Marek's disease as accounted by 1.65 per cent of the birds, while those vaccinated at the rate of 250 PFU were not properly protected, showing a higher morbidity rate--9.23 per cent. It is concluded that the Bulgarian vaccine--strain C3-1--confers solid immunity in a dose of 500 PFU, the vaccination of broilers being economically profitable.