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Biomedical subjects

M Ignatova

Publications and source records attributed to M Ignatova.

11 recordsLinked to original sources
PubMed2006

Design of antibacterial surfaces by a combination of electrochemistry and controlled radical polymerization.

In this paper we report a new method for the electrochemical deposition of a metal/polymer composite layer on a conducting substrate. The electrochemical solution is a mixture of an acrylate (ethyl acrylate, EA; 2-phenyl-2-(2,2,6,6-tetramethylpiperidin-1-yloxy)ethyl acrylate, PTEA; 8-quinolinyl acrylate, 8QA), a metallic salt (silver(I) acetate), and a conducting salt in dimethylformamide. The process has been first studied with EA as the polymer precursor and then extended to PTEA and 8QA, respectively, with the purpose to prepare antibacterial surfaces. The final coating has been characterized by attenuated total reflection Fourier transform infrared spectroscopy, energy-dispersive X-ray analysis, environmental scanning electron microscopy, and atomic force microscopy. All the silver-containing coatings were effective against Gram-negative bacteria Escherichia coli. Bacteria Staphylococcus aureus could not adhere to the Ag(0)/polyacrylate films deposited on stainless steel.

Acetates↗
PubMed2003

Preparation of reactive surfaces by electrografting.

The electrografting process has been applied to a new monomer in order to induce reactivity to the surface of various conducting substrates which are then appropriate for the anchoring of a large variety of molecules (catalysts, proteins, amino-polymers etc.).

Journal Article↗
PubMed1987

[Use of gamma-globulins from the peritoneal fluid of cats with infectious peritonitis for the immunofluorescence demonstration of the TGE antigen].

Peritoneal exudate of a cat affected with feline infectious peritonitis (FIP) was used to isolate an IgG-globulin, employing affinity chromatography, and conjugate it with fluorescein isothiocyanate. The conjugate was tested on cross sections of the small intestine of a pig infected with strain Miller-3 of the transmissive gastroenteritis (TGE) virus, simultaneously with an anti-TGE conjugate of an SPF pig. Identical results were obtained with both conjugates, however, the anti-FIP conjugate had a several-times higher titer. Discussed are the possibilities and advantages of using the anti-FIP conjugate in the immunofluorescence demonstration of the TGE virus antigen.

Animals↗
PubMed1987

[Etiological study of viral gastroenteritis in swine].

Studied were the etiology and spread of nonbacterial gastroenteritis in pigs over a period of five years. Ascertained were cases of diarrhea caused by the virus of transmissive gastroenteritis, epizootic diarrhea, and rotaviruses. The transmissive gastroenteritis virus was found in 14.1 per cent of the investigated material, mostly in the winter months (67.8 per cent), which was 65.6 per cent of the positive cases. The number of cases and that of the farms involved abruptly rose in the last two years of the investigated period when as many as 73.4 per cent of the positive findings were recorded. Thirty to 37.7 per cent of the studied farms proved to be infected. Enzootic diarrhea was recorded on seven out of the 12 studied farms, whereas 30 to 50 per cent of the sampled material was positive. The serologic study of reconvalescent blood sera of pigs from three infected farms revealed that 90 up to 100 per cent of them contained antibodies. In a great part of the sera (from 15 to 68.9 per cent) there were transmissive gastroenteritis antibodies as well. In 6.8 per cent of the Investigated samples and on 30 per cent of the farms there were also findings of rotaviruses. Cases of rotavirus gastroenteritis were recorded the year round with a rising trend in the cold months. Antibodies to these viruses were established on a large scale--from 58.13 to 100 per cent. There were also mixed infections--corona- and rotaviruses or viruses and bacteria.

Animals↗
PubMed1987

[Pathomorphological changes in the small intestine of pigs with rotavirus diarrhea].

Studied were the pathohistological changes and the morphologic-structural injuries of intestinal mucosa of pigs (5-7 days old), spontaneously affected with rotavirus diarrhea, raised by traditional methods. Simultaneously with the rotavirus invasion was established Isospora suis. In spite of the early time of the disorder (the test was carried out 24 hours after the appearance of the first clinical symptoms) there were established different in degree and expression morphologic changes; atrophy and fusion of the fibrils, replacement of the cylindrical epithelium with cubic, dystrophy and exfoliation of the enterocytes with exposure of the lamina propria. The burden of the dystrophic processes, which has affected the intestinal mycosis, was registered by scanning electronic microscopy. The dystrophic processes start at the top of the intestinal fibrils, the fusion of the fibrils spreads over a big number of them, forming a conglomerate mass. Simultaneously with the fibrils, affected by dystrophy, were observed fibrils with normal shape and size. During immunofluorescent examinations also is observed focal distribution of enterocytes, containing antigen on some of the fibrils. Now is discussed the importance of the pathogenic microflora, in the intestinal track of pigs, raised by traditional methods, for the early appearance and for the burden of the morphologic-structural changes.

Animals↗
PubMed1986

[Epizootic enteritis in pigs].

Studied was the etiology of diarrhea in sucking pigs, using animals aged up to seven days, that had suffered from the disease not longer than 24 hours on 12 farms. There were cases of diarrhea induced by the virus of epidemic diarrhea. The virus was characterized morphologically through electron microscopy, and antigenically through direct immunofluorescence and serologic investigation. The disease was distinguished from transmissive gastroenteritis via differential diagnosis. Demonstrated was the lack of cross antigenic relation between the two viruses.

Animals↗
PubMed1984

[Cytomorphological and cytochemical studies on the multiplication of bovine reovirus type 1 in a cell culture].

Parallel cytomorphologic and cytochemical studies were carried out on the replication of the bovine reovirus type 1 in the Vero cell line. It was found that a high multiplicity of infection M = 5 the first morphologic changes took place some 12 hours following infection, while at the 24th hour there appeared also the characteristic inclusion bodies. At the same time the appearance was noted of acidophile masses in the cytoplasm of some of the infected cells. The morphologic changes reached the peak values of their development at the 48th hour, and the cytoplasmic inclusions assumed a net-shaped structure of lower density. It was also found that following a short-term rise in the first 12 hours after infection there set in a general suppression of the RNA-containing material, which spread irregularly through-out the cell thus marking the nonpyroninophile viral inclusions. The desoxiribonucleic synthesis was not visibly affected, however, the nuclear chromatin remained with an unchanged structure. The viral inclusions were Feulgen PAS-negative. The hydrolytic enzymes alkaline and acid phosphatase and 5-nucleotidase were strongly inhibited after a short-term rise within the first 12 hours of infection.

5'-Nucleotidase↗
PubMed1984

[Immunofluorescence and electron microscopy study of bovine reovirus multiplication in cell culture].

The appearance and development of reovirus antigens was followed up in Vero cells. The earliest immunofluorescence finding was established at the 6th hr, consisting in the appearance of small shining granules in and around the nuclear cytoplasm. At the 24th hr in 15 per cent of the cells there was a positive immunofluorescence finding in the form of one or several objects grouped closely to the nucleus. At the 36th hr fluorescence was seen in about 50 per cent of the cells to surround the nucleus and fill the whole cytoplasm or appearing as a limited and demarkated one. By form the fluorescent objects resembled viral inclusions. The immunofluorescence finding reached its peak at the 48th hr. In cells infected with Reo 2 the appearance and cumulation of the virus antigen ran its course in the same sequence as that seen with Reo 1, however, it was manifested with higher intensity. The electron-microscopic study of Reo 1-infected cells revealed greater diversity in the stages of infection as early as the 24th hr--from the appearance of sporadic virions up to the emergence of large virus crystals the virions in which assumed square or hexagonal arrangement. There was also linear arrangement of the virions by the length of the tubular cell structures. Cells infected with Reo 1 and Reo 2 presented likewise zones with large masses of virus matrix prior to the appearance in them of new virions. There was also particular cumulation of the cell ribosomes along with the matrix formation. It is believed that the appearance of these formations is associated with the virus morphogenesis.

Animals↗
PubMed1983

Hereditary nephritis and hypoplastic dysplastic nephropathy: hydroxylysine glycoside excretion and the glomerular basement membrane.

Eleven children aged 5 to 15 years with hereditary nephritis and twelve children with hypoplastic dysplastic nephropathy were studied. The children with hereditary nephritis were divided into 2 groups while correlating the level of renal excretion of hydroxylysine glycosides (HOLG) with ultrastructure of glomerular basement membrane. The first group was characterized by decreased urinary excretion of HOLG and extremely thin basement membranes, the second one - by increased HOLG excretion and thickened membranes, The children with hypoplastic dysplastic nephropathy which were divided into 2 groups according to HOLG excretion differed in presence or absence of anatomic anomalies and in the number of connective tissue dysembryogenetic stigmata. The data are suggestive of an important role and diversity of metabolic derangement of the collagenic component of basement membranes in the pathogenesis of the diseases studied.

Adolescent↗
PubMed1982

[Karyological study of a long-term cell culture of calf kidney].

Studied was the karyologic type of a long-term calf kidney cell culture. The optimal conditions were found for the preparation of good metaphase plaques of such cell culture, with clearly visible chromosomes. The changes in the chromosomes, setting in at the level of the 1st, 10th, 20th, and 27th passage were followed up. While the chromosomes in the first passage did not show any visible changes (with the exception of the 3rd chromosome where the presence of satelites was found), these underwent structural changes that started in the tenth passage, reached their peak in the twentieth passage, and receded later on. The most frequently encountered structural changes were the isochromosome gaps, dicentric configurations, acentric fragments, and polyploidy that appeared at the level of the 27th passage in four out of the twenty metaphase plaques. Discussed is the importance of the structural changes found.

Animals↗