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Biomedical subjects

G Popov

Publications and source records attributed to G Popov.

At least 37 records · Page 2Linked to original sources
PubMed1982

[Morphological and morphogenetic characteristics of Chlamydia infection in sick animals].

Studies were carried out on the morphology and the morphogenesis of the Chlamydia organisms in animals with various Chlamydia infections. A total of 255 samples of placentae and parenchymal organs were investigated via the electron microscope, using the ultrathin section method and the negative contrasting method. A characteristic was made of Chlamydia infections in sheep, goats, cows, wild murine rodents, and birds. It was found that the morphologic and morphogenetic aspects of Chlamydia reproduction in diseased animals were the same as those described previously in the yolk sacs of chick embryos. The morphology of Chlamydia organisms in the viscera of animals with Chlamydia infections, and particularly in placentae of sheep that miscarried was characterized by the accumulation of elementary and initial bodies--condense, reticular, and intermediary. It was concluded that the morphogenesis of Chlamydia in animals with infections caused by Chlamydia represented a many sided morphologic process characterized by the following more important aspects: chlamydial matrix, initial chlamydial vacuoles, autonomic synthesis of chlamydial bodies in the initial vacuoles and the chlamydial matrix, high production of Chlamydia membranes, and accumulation of polymorphous Chlamydia bodies. Essential in the reproduction of Chlamydia was their massing into and around the capillaries.

Abortion, Veterinary↗
PubMed1982

[Diagnostic methods in chlamydial abortion in sheep].

Vast serologic, virologic, and morphologic investigations were carried out into the Chlamydial abortion in sheep. Use was made of the complement-fixation test, passive hemagglutination, chick embryos, electron microscopy, concentration, and purification. The disease was demonstrated on a number of farms with the single or combined employment of the above methods. Discussed was the problem of the diagnostic value of the single and twofold titrations of serum samples from sheep that had miscarried. Prerequisites were developed for the modern use and improvement of the serodiagnostics through the application of more sensitive serologic reactions on the base of purified and concentrated Chlamydial antigens. An important condition to confirm and accelerate the isolation of the strains was said to be the employment of electron microscopy both as a prompt and precise method for the early morphologic identification of the Chlamydial isolates and as a precise control on the serial culturing of the strains. Perfected was the morphologic diagnosis of the Chlamydial abortion in sheep through introducing for the first time of direct electron microscopy of negatively contrasting suspensions and ultrathin cross sections of placentae and viscera of aborted fetuses. The method was shown to be precise, demonstrative, and highly effective. It was employed successfully in sheep with mixed infections--Chlamydia and Salmonella, Chlamydia and Listeria, etc.

Abortion, Veterinary↗
PubMed1982

[Electron microscope diagnosis of Chlamydia infections].

A comprehensive study was carried out on the electron microscope diagnostics of Chlamydia in diseased animals, birds, and humans. Studied were ultra thin cross sections, and negative-contrast microscopy was employed in the investigation of a total of 953 clinical, pathologic, and laboratory-and-experimental samples from animals, birds, and humans suspective of being carriers of Chlamydial infections. The investigations were performed in 21 nosologic units. In more than one half of the samples there were elementary and initial bodies. It was found that the direct electron microscopy of Chlamydia in clinical and pathological materials was a very valuable method. Its use for the early morphologic indication and identification of the Chlamydial isolates in chick embryons proved highly effective. Such wider study on the diagnostic value of electron microscopy with Chlamydial infections was carried out for the first time. The results obtained spoke of the fact that it was highly efficient and promising with Chlamydia. Its basic qualities in such case were shown to consist in its promptness, demonstrativeness, and hermlessness. Besides, it proved to be much less time-consuming, up-to-date, and of relatively low primary cost. These characters of the method pointed to its superiority to the conventional morphologic methods making use of the light microscope.

Animals↗
PubMed1981

[Chlamydial polyarthritis in calves].

Investigations were carried out on some farms to establish the presence of Chlamydia organisms in spontaneous cases of polyarthritis in calves. Use was made of various methods--chick embryos, light and electron microscopy, and the complement-fixation test (CFT). As many as 9 C. psittaci strains were isolated from synovial liquid of calves affected with polyarthritis from 6 farms in several districts of the country. The isolated strains were identified morphologically by means of electron and light microscope, and serologically--through demonstrating the presence of a group-specific Chlamydia antigen by CFT with a known positive anti-chlamydial serum. There were in the sera of some calves with polyarthritis chlamydial KC-antibodies. Results spoke of the chlamydial etiology of some polyarthritis diseases in calves in this country, confirming and supplementing previous observations of the authors.

Animals↗
PubMed1981

[Production of labelled gamma globulin for the detection of Chlamydia].

A method was worked out for the production of an antichlamydial fluorescent serum to be used in the direct immunofluorescence test. Used were the methods of culturing Chlamydia in chick embryos and cell cultures, light and electron microscopy, differential centrifugation and supercentrifugation, gel chromatography in Sepharose, ultracentrifugation in saccharose, hyperimmunization of guinea pigs, conjugation of gammaglobulin with fluorescein isothiocyanate, complement fixation, and the direct immunofluorescence itself. Applied was a new immunologic scheme for the production of fluorescent sera. The guinea pigs were hyperimmunized twice and three times at 30-day intervals with highly purified, highly concentrated and adjuvant-treated chlamydial suspensions. It was concluded that the main condition for the production of high titer labelled gammaglobulins was to obtain purified and concentrated chlamydial antigens and use these with an adjuvant. To indicate Chlamydia in testing the conjugates it is essential to prepare standard test lamellas infected at high multiplicity of purified and concentrated Chlamydia.

Animals↗
PubMed1981

[Method of obtaining concentrated and purified chlamydial suspensions].

A method was worked out to obtain concentrated and purified chlamydial suspensions. Used were differential centrifugation and super-centrifugation, gel filtration on sepharose, and ultracentrifugation on saccharose substrate. The new method was successfully employed in electron microscopic, immunologic, and immunofluorescence investigations. As a result of its use in electron microscopy studies were carried out on the morphology of the purified chlamydial particles in ultra thin sections and negatively contrasting preparations. Immunologic studies led to the production of high-titer hyperimmune sera from guinea pigs. Such native sera were successfully used to obtain high-titer fluorescent sera.

Animals↗
PubMed1980

[Morphogenesis of Chlamydia].

A morphological investigation was carried out on more than 12 chlamydia strains of avian and mammalian origin, multiplied in chick embryos. A number of investigations were carried out under an electronic microscope, including 674 samples of concentrated and purified chlamydia as well as yolk sacs in ultrathin sections and in negatively contrasted preparations. In the cytoplasm of the cells we proved the presence of a chlamydial matrix, an autonomous synthesis of chlamydial bodies, the morphology and polymorphism of the chlamydiae, as well as the degenerative changes in the endodermal and endothelial cells in the yolk sacs of the chick embryos. Conclusions were drawn out that in the development of chlamydia in the chick embryos no intertransformation of chlamydial bodies and no binary divisions are observed, i.e. there are no proofs of the so-called cycle of development. The development of chlamydia in chick embryos takes place in the form of specific chlamydia morphogenesis which is characterized by an autonomous synthesis and morphogenesis of chlamydia bodies on the basis of a multivacuolated matrix.

Animals↗
PubMed1979

[Isolation of the bovine herpesvirus-3 from sick calves].

Three herpes strains identified as herpes virus-3 were isolated in revolving test-tubes with cell cultures of nasal samples and lung parenchyma from diseased calves at the time of a respiratory enzooty. Large crystalloid aggregates of herpes virus virions were observed in the nucleus and in the cytoplasma by the electron-microscopic investigation performed on infected cell cultures. The experimental infection of calves with the isolated strain produced slight symptoms of respiratory disease in single calves only. The infected calves were susceptible to a following infection with cattle herpes virus-1.

Animals↗
PubMed1979

[Hemagglutinating activity and morphology of antigen K 99 in enterotoxic strains of E. coli isolated from calves].

The hemagglutination activity and morphology of antigen K 99 in enterotoxic E. coli strains isolated from calves was studied. It was proven that antigen K 99 is produced not at 18 degrees C, but at 37 degrees C. All K 99+ E. coli strains react with absorbed anti K 99 serum, showing various anti-agglutination titers. The hemagglutination activity of K 99+ E. coli strains is inhibited by absorbed K 99 antiserum. In immunodiffuse tests all K 99+ E. coli strains react by producing a single precipitation line. It is proven electronmicroscopically that on the surface of the bacterial cell of K 99+ E. coli strains is observed a filamentous structure, consisting of numerous fine fibers which give it a fibriform outlook. No such morphological structures are observed in K 99- E. coli strains.

Absorption↗
PubMed1978

[Corona- and rotavirus enteritis in newborn calves in Bulgaria].

In the course of investigations into enteritis enzootics in newly-born calves, 55 fecal samples have been studied through direct electron microscopy by the negative contrast method. Rota viruses were found in eight of them, corona viruses in 38.2 per cent of the cases, and both rota- and corona viruses in 49.1 per cent of the cases. Two types of rota-viral particles were observed: with and without supercapsids. Also two types of corona-viral particles were established. The first type was relatively monomorphic, having an average diameter of 120 nm, and length of the surface spikes of 20 nm. The second type was pleomorphic with length of the spikes of 11 nm. Most of the fecal samples, containing corona viruses, agglutinate mice, rat and hamster erythrocytes. On studying the physical and chemical properties of the hemagglutinine, ist gradient density and antigenic patterns it was shown that it is related to the intact corona-virions. With the hemagglutination-inhibition test developed, antibodies against corona-viruses in the sera of a considerable number of the cows have been demonstrated. A precipitating antigen has been shown in a part of the fecal samples, containing rota-viruses. By studying the physical and chemical properties, its gradient density and its comparison with a refernce antigen, it has been shown that the antigen was conditioned by degraded fragments of rota-viruses. With the aid of the immunodiffusion method with a fecal antigen evolved, precipitating antibodies have been shown in 18 to 46 per cent of the cows and calves.

Animals↗
PubMed1978

[Density gradient and ultrastructure of bovine adenovirus type 1].

Isolated and purified were virions and hexones from the bovine adenovirus type 1. The infectious virions were of equilibrium density of 1.34 g/cm3, and the empty capsids--of 1.305 g/cm3. The virions had a facet length of 43.5 nm, their size being 82.7 nm (distance between opposite poles) to 74.0 nm (diameter of the virion). The fibers of the bovine adenovirus type 1 measured 26.0--28.0 nm. The virus was destroyed by 30 per cent formamide, yielding free hexones of 1.290 g/cm3 of equlibrium density. The hexones were 10.0-12.0 nm high, were thicker at their base, and possessed a central cavity. Beside single hexones groups of 9 hexones each were also found in the soluble components (being of a left and a right type according to the arrangement of the capsomeres in them). It was demonstrated serologically that the hexones possessed 2 antigen determinants which retained their antigenic activity even after the hexones degraded and lost their morphologic type.

Adenoviridae↗
PubMed1978

[Use of new Bulgarian hydrosol vitamin preparations in veterinary medicine].

Studied were the new Bulgarian hydrosol preparations Hydro-AD3EC, Hydro-AD3EK, and Hydro-EC. Their tolerance was investigated with the use of albino Wistar rats, the resorption and retention (by their liver content) of retinol and d, 1-alfa-tocopherol was investigated in young broiler chickens, the resorption of ascorbic acid was followed up in White English layers, the antihemorrhagic effect of Hydro-AD3EK was studied in rats with experimentally induced hemorrhagic diathesis offering 30 mg ethyl biscoumacetate (pellentan tablets) with the feed. It was found that the oral application of the first three hydrosol preparations to albino rats at the rate of 12.5 cm3/body weight (equal to 10-15 effective doses for birds) did not produce toxic effects. The retinol and d, 1-alfa-tocopherol constituents of AD3EC and AD3EK, given with the drinking water to birds, were well resorbed and were deposited in the liver. Fuller resorption was observed with the use of AD3EC. The ascorbic acid of AD3EC and AD3EK when these were offered per os to adult chickens was resorbed quickly, which was better expressed with AD3EC. AD3EK in oral application to rats produced antihemorrhagic effects. The use of these preparations in a prophylactic scheme with young broilers shortened the fattening period and improved the feed conversion.

Absorption↗
PubMed1977

[Electron microscopic studies of Pasteurella multocida bacteriophages].

Studied was the morphology of four Pasteurella multocida phages, Nos. 115, 32, 967, and 1075, with the use of an electron microscope. The bacterial phages had hexagonal heads of a 55 x 55 nm diameter, and were of an isometric polygonal form themselves. The tail of the phages was 120 nm long and was non-contractile. By these characters the P. multocida phages are to be referred to the morphologic group of phages of noncontractile tails--group B after Bradley and group IV after Tihonenko.

Bacteriophages↗
PubMed1977

[Morphology of bovine adenovirus type I].

Electron-microscopic studies were carried out on a concentrated and purified adenovirus type I. It was found that its morphologic aspects were characteristic of the adenovirus group. In the preparations of this virus there were large amounts of incomplete virions and soluble components--hexons, groups of hexons and pentons. Some of the virions were grouped in p-crystal structures or were released as grouped in cell vacuoles. The hexons presented a six-angle contour and a central cavity. The pentons possessed fibre components that were comparatively long. The presence of free pentons spoke of the existence of incomplete hemagglutinins.

Adenoviridae↗