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Biomedical subjects

V Kolev

Publications and source records attributed to V Kolev.

46 records · Page 3Linked to original sources
PubMed1987

[Experimental Salmonella dublin infection in calves].

Calves, aged 20 days, were experimentally infected with Salmonella dublin. The animals of one-group were treated at the rate of 6.10(8), and those of another--at 2.10(10) up to 4.10(10) live bacterial cells. The calves of the first group showed no clear clinical symptoms of a disease; neither did they manifest regular shedding of bacterial cells. The calves of the second group presented a typical clinical picture, with more regular shedding of bacteria through nasal discharges and the feces. After killing the animals Salmonella dublin organisms were found in all parenchymal organs and in the lymph nodes. Morphologically, the prevalence was established of inflammatory necrobiotic processes in the liver, with activation and proliferation of the sinus endothelium of the lymph nodes, and catarrhal inflammation of varying manifestation in the small intestine.

Animals↗
PubMed1986

Spatio-temporal organization of bioelectrical processes in the nervous-system--its functional significance and complex quantitative estimation by means of spectral and coherent analyses.

The review of our research and the data in the literature shows that application of the systems approach and the complex quantitative analysis of local processes and spatio-temporal organization of bioelectrical activity in the nervous system provides better possibilities for the discovery and investigation of functionally significant changes, often discrete, appearing in the course of investigations performed under normal physiological conditions in man and in freely moving animals, as well as for the estimation of changes beyond the limits of homeostasis.

Animals↗
PubMed1983

[Intrauterine bacterial and mycotic infections in cows].

Bacteriologic, mycologic, and serologic investigations of cows and calves and three experiments with rabbits were carried out to shed light on the bacteriology and mycology of the intrauterine infections in cows. The following organisms were isolated from the investigated cows that exhibited disturbances in their reproduction, and had abortions, or gave birth to calves that were affected with diseases or died: Escherichia coli (17.84%), association of bacteria (7.64%); Vibrio genitalis (3.86%); Streptococcus sp. (2.78%); moulds (2.54%); Staphylococcus aureus (2.20%); Proteus sp. (1.62%); Staphylococcus epidermidis (1.39%); Pseudomonas aeruginosa (1.39%); Pasteurella multocida (0.11%). The serologic investigation of a total of 231 blood samples from cows that miscarried, gave birth to dead calves, or failed to conceive revealed that in 15.58 per cent there was vibriosis, and in 6.06 per cent--leptospirosis. Demonstrated was the etiologic link between cows with reproductive disturbances and diseased calves with regard to vibriosis and leptospirosis. The tests with rabbits were indicative of bacterial carriers (with special reference to the genitalia) up to the 60th day following infection. There were abortions, sterility, and death cases and the birth of unviable bunnies in the case of reproduced coital infections with Escherichia coli and Pseudomonas aeruginosa.

Abortion, Veterinary↗
PubMed1977

[Studies of the etiology of infectious abortion in cows in Ruse District].

A total of 28,159 blood serum samples have been examined for brucellosis, 87--for leptospirosis, 84--for toxoplasmosis, 554--for the presence of rickettsii and neoreckettsii, and 193--for total protein content, albumin, and protein fractions, taken from cows in the course of the years on 40 dairy farms in the district of Rousse. Bacteriologically were examined 349 aborted fetuses, 178 samples of estral secretion, 57 placentae, and 1002 samples of washings and seminal fluid from bulls for vibriosis. Bacteriologic investigations were also carried out on 383 fetuses for salmonellosis, listeriosis, and colibacteriosis, and virologic studies of 398 placentae and parenchymal organs of fetuses. Twenty-eight fetuses were studied parasitologically for toxoplasmosis, and 118 blood smears were examined for hemosporidiosis. It was established that most important in the etiology of the infectious abortions in cows in the district of Rousse were Vibrio organisms. They were found in 36.9 per cent of the studied bovine fetuses and in 24.4 per cent of all materials examined bacteriologically. Only 4 cases were noted of neorickettsii from fetuses and placentae. Serologically, there were 23.6 per cent cases positive for neorickettsiosis, and 12.6 per cent--for Q fever; 56.4 per cent of the investigated sera proved positive for leptospirosis. In 0.8 per cent of the examined fetuses there was Escherichia coli. Abortions in cows were also due to anaplasmosis and francaillelosis; 14.2 per cent of the investigated respective sera were positive for toxoplasmosis. On the days of abortions the amount of total protein was 7.13 mg%, that of albumins--36%, and of globulins--64%. It is considered imperative to elucidate the cause of abortions of infectious nature in cows in connection with the establishing of cattle-breeding complexes.

Abortion, Veterinary↗
PubMed1976

[Epizootiological and parasitological status of the flocks at a poultry combine].

A comprehensive epizootiologic study has been carried out at one of the large poultry dressing combines in this country. Results have shown that the part played by infections as against the remaining diseases established in the various technologic categories is as follows: 9 to 23.8 per cent in growing parents; 16.0 to 24.6 per cent in adult parents; and 4.8 to 13.4 per cent in broilers. So far as parasitic diseases are concerned the respective figures are 3.2 to 9.9 per cent, 3.0 to 3.3. per cent, and 2.9 to 3.0 to per cent. The import of birds from France and England intended for satisfying the needs of the poultry dressing combine in Roussé has contributed to the introduction of infections which have later on assumed an epizootic course, such as infections encephalomyelitis, infectious bronchitis, and Marek' disease. The epizootic status has been aggravated with the development of a number of diseases already existing in this country--fowl pox, lymphoid leukosis, chronic respiratory disease, salmonellosis, and above all infections caused by the so-called occasionally pathogenic agents--coli organisms, staphylococci, and Pseudomonas. Of the parasitic diseases only coccidiosis has developed, being caused by a variety of species: Eimeria acervulina, Eimeria necatrix, Eimeria maxima, Eimeria muvati and Eimeria tenella. The absence of helminth infections is due to the routinely adopted technological practice of raising birds in confinement and the strict veterinary control and guard. On the basis of the results obtained and the conclusions drawn some more effective prophylactic measures are suggested correcting and supplementing the existing prophylactic programme.

Animals↗
PubMed1976

[Study of the pathogenicity and drug sensitivity of staphylococci isolated from poultry].

Studied were the pathogenicity and drug sensitivity of a total of 64 Staphylococcus strains isolated from chickens and chick embryos. A high per cent value of coincidence was established between the tests of positive plasma-coagulase reaction, hemolysis, golden-yellow pigment production, glucose-positive reaction in anaerobiosis and the lethal sequela following the experimental infection of young chickens and albino mice. The complex use of these tests proved to be a dependable criterion of pathogenicity. Most of the Staphylococcus strains were shown to be strongly and moderately sensitive to kanamycin gallimycin, oximycin, chloramphenicol, and persistent to oxitetracyclin.

Animals↗
PubMedDate not supplied

Event-related prolongation of induced EEG rhythmicities in experiments with a cognitive task.

Since we consider evoked potentials (EPs) and event-related potentials (ERPs) as an ensemble of induced rhythmicities we investigated "sensory" evoked potentials (EPs) and "cognitive" event-related potentials (ERPs) with respect to their frequency components (around 5 Hz and around 10 Hz). "Sensory" EP sessions consisted in standard EP measurements with tone bursts of 2000 Hz frequency. Prior to the subsequent "cognitive" sessions, the subjects were instructed to expect frequent 2000 Hz tones and rare 1950 Hz tones, the rare tones thus being difficult to detect. A further instruction was to count the number of the "rare" stimuli. Not a single tone of different frequency, however, was presented. The single trials were then analyzed with respect to their 5 Hz and 10 Hz components. Time-locking was investigated using a modified single sweep wave identification (SSWI) method. Depending on features of the prestimulus EEG, it was observed that theta (4-7 Hz) and alpha (7-13 Hz) responses were prolonged in the case of "cognitive" sessions. We believe that the prolonged endogenous ERP components are induced rhythmicities triggered by additional information processing, when a high degree of uncertainty has to be resolved during our experimental conditions. For the analysis and visualization of these phenomena, the combination of digital filtering and SSWI showed relevant advantages in comparison to other methods.

Acoustic Stimulation↗