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Biomedical subjects

Z Nikolova

Publications and source records attributed to Z Nikolova.

12 recordsLinked to original sources
PubMed1995

Demonstration of nitric oxide synthase (NOS) in marmosets by NADPH diaphorase (NADPH-d) histochemistry and NOS immunoreactivity.

Since species interdiversity often prevents the extrapolation of laboratory rodent data to man and similar problems may exist for nitric oxide synthase (NOS), NADPH-d activity and immunohistochemistry of NOS were investigated in the New World monkey Callithrix jacchus (marmoset), which has been shown to be close to the human situation in many respects. Using the NADPHd reaction with beta-NADPH and nitroblue tetrazolium (NBT) on acetone-chloroform pretreated cryosections, NBT formazan was found in many neural and non-neural (e.g. diverse epithelia, striated muscle fibers, vascular endothelium) cells in numerous tissues and organs. Prefixation with formaldehyde lowered the number of NADPH-d active sites and the amount of formazan with the exception of neuronal NADPH-d as did incubation of fresh or acetone-chloroform-pretreated sections for NADPH-d in the presence of 0.5% formaldehyde. When 1% formaldehyde or 0.5 mM permanganate were used significant amounts of formazan appeared only in central and peripheral neurons, vasal endothelial cells, small intestinal enterocytes, plasma membrane region of striated muscle fibers as well as arteriolar cells in the kidney; except for enterocytes, these observations were confirmed by NOS-immunohistochemistry which revealed in addition reactive cells in the thymus and intestinal lamina propria.

Acetone↗
PubMed1992

[The laboratory epidemiological study of the joint circulation of the influenza virus A subtypes A/H1N1/ and A/H3N2/ in Bulgaria].

The National Influenza Center of Bulgaria made the epidemiological analysis of the spread of influenza virus, type A, for the period of 11 years on the basis of mass laboratory investigations. Subtype A (H1N1) was found to be the main factor of epidemics in 1978 and 1982, while the epidemics of 1980, 1983, 1985, 1986, 1987 and 1988 were mainly caused by subtype A (H3N2). The data of laboratory and epidemiological studies indicated that after 20-year absence influenza virus A, subtype A (H1N1), was found again to circulate among the population of Bulgaria, and in 1978-1988 circulated simultaneously with the previous subtype A (H3N2). The simultaneous circulation of two subtypes of influenza virus was of great importance for the frequency, spread and duration of influenza epidemics.

Bulgaria↗
PubMed1981

[Influenza epizootic in swine due to strain A (Victoria/3/75 H3N2)].

Studies were carried out on the first grippe epizootic in pigs in Bulgaria. The affected animals showed a rise in temperature (40.5 to 41.8 degrees C), loss of appetite, abdominal type of respiration, and noisy and painful cough. The infection ran its course with a picture typical of a virus disease which did not respond to broad-spectrum antibiotic treatment. On an average the duration of the clinical course lasted 4 to 5 days, affecting almost all swine on a pig breeding farm, with single death cases. The morphologic changes observed in animals killed for diagnostic purposes were typical of a grippe infection. Isolated was a grippe virus A (Antimovo) 1/80/H3N2) the preliminary typisation of which showed close relation to strain A (victoria) 3/75/H3N2/. Serologic investigations using double blood samples from the affected pigs in double immunodiffusion test and hemagglutination-inhibition test demonstrated the etiologic role played by the isolated grippe virus.

Animals↗
PubMedDate not supplied

[Interepidemic influenza in Bulgaria based on laboratory research data].

During the interepidemic periods of 34 years (1955-1988) the National Influenza Centre of Bulgaria with the aid of 11 supporting stations investigated a total of 27240 nasopharyngeal washings and 42530 paired sera of patients with acute respiratory diseases. Eighty strains of subtype A (H1N1) influenza virus, 60 strains of subtype a (H2N2), 148 strains of subtype A (H3N2), 3 strains of subtype A (Heg2, Neg2), 2 strains of subtype A (Hsw1N1), 14 strains of type B, and 6 strains of type C were isolated. Serologically positive results for influenza were observed in 12.65% for influenza type A virus, 3.83% for type B, and 1.78% for type C (on the whole in 18.26%). The data obtained enable to recommend that practicing physicians should not hesitate to make the diagnosis of influenza during the interepidemic periods on the basis of sufficient clinical and especially epidemiological data and should actively try to get the laboratory verification of the preliminary diagnosis.

Antibodies, Viral↗
PubMedDate not supplied

[Study of human influenza viruses isolated in 1982 which are antigenically related to the swine flu virus].

Influenza A viruses (H1N1 serovariant) antigenically related to swine influenza viruses were isolated in March, 1982, from two sick adolescents in a rural area of Bulgaria who had had contacts with each other and with animals. The isolates, A/PRB/120/82 and A/PRB/121/82, were found to have hemagglutinin containing antigenic regions typical of hemagglutinin of both A/New Jersey/8/76 strain and A/swine/Finister/HG/82 strain. Because of the unusual structure of hemagglutinin, it is assumed that these viruses have not been introduced into Europe from the American continent. The limited nature of the outbreak is associated with the presence in virions of A/PRB/120/82 and A/PRB/121/82 strains of NP-protein typical of animal influenza viruses.

Adolescent↗
PubMedDate not supplied

[Age profile of the antihemagglutinins and antineuraminidase antibodies in type A influenza (author's transl)].

Antineuraminidase and antihemagglutinating antibody studies were carried out in parallel in sera from subjects born in Bulgaria in 1968-1972, 1956-1960, 1946-1950, 1925-1935 and 1917-1920. It was found that the amount of both antineuraminidase and antihemagglutinating antibody in sera from normal subjects could vary depending upon the year of birth and the strain used for the test. The antibody spectrum was most narrow in children under 4 and wider in subjects born before 1925. Serograms of the age distribution of antineuraminidase antibody were different in 4 out of 5 strains used which confirmed the hypothesis of Francis and Davenport of the more solid immunological response to the first exposure to virus. Parallel examinations of the antibody spectrum in human sera confirmed differences in the antigenic specificity of the "active center" of neuraminidases of A/Hong Kong/1/68 (H3N2) and A/Singapore/1/57 (H2N2) viruses and for the first time provided evidence attesting to the existence of similar strain differences in neuraminidases belonging to the N1 group. Examinations for antineuraminidase antibody in addition to antihemagglutinins increase the effectiveness of evaluation of the immunological structure of the population.

Adolescent↗
PubMedDate not supplied

[Antigenic characteristics of different variants of influenza virus A(H3/N2) and their circulation in the USSR and People's Republic of Bulgaria in 1968-1980].

Influenza A (H3N2) virus strains isolated in 1968-1980 in the USSR (1908 strains), PRB (1413 strains) and in other countries were studied comparatively. Among 15 drift variants described in the literature only 6 were found to have sequential epidemic spread. In all the instances the epidemics occurred after importation of the virus from abroad, the interval between the emergence of a new drift variant and its detection in the study areas ranged from 2 1/2 months to 1 1/2 years and was not synchronous for the USSR and PRB. A progressive decrease of the antigenic determinant typical of the prototype A/Hong Kong/1/68 in hemagglutinin and neuraminidase of the drift variants was observed. The strains isolated in 1979-1980 were not directly related to the A/Hong Kong/1/68 strain but were connected with it through intermediate variants circulating in 1974-1975.

Antigens, Viral↗