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Biomedical subjects

K Kolev

Publications and source records attributed to K Kolev.

At least 37 records · Page 2Linked to original sources
PubMed1994

Heparin modulation of the fibrinolytic activity of plasmin, miniplasmin and neutrophil leukocyte elastase in the presence of plasma protease inhibitors.

The effect of heparin on the inactivation rates of fibrin-bound plasmin, miniplasmin and neutrophil leukocyte elastase (PMN-elastase) by their plasma inhibitors was studied. While plasmin and miniplasmin bound to fibrin are not inactivated by antithrombin, heparin (800 nM) makes these enzymes available for the inhibitor; the second-order rate constant increases from zero to 1.3 x 10(3) M-1 s-1 and 3.3 x 10(3) M-1 s-1, respectively. Heparin slightly increases the rate of fibrin-bound enzyme inactivation by plasmin inhibitor. alpha 1-Protease inhibitor, on the other hand, is unable to inactivate plasmin or miniplasmin bound to fibrin and heparin has no facilitating effect. In the case of PMN-elastase, heparin (300 nM) further increases enzyme protection against alpha 1-protease inhibitor; the rate constant decreases from 41 x 10(3) M-1 s-1 to 23 x 10(3) M-1 s-1. alpha 2-Macroglobulin inhibits fibrin-bound miniplasmin and PMN-elastase with a second-order rate constant of 1.8 x 10(4) M-1 s-1 and heparin (300 nM) increases the rate insignificantly for miniplasmin and by a factor of two for PMN-elastase. It is remarkable that plasmin bound to fibrin is not inhibited by alpha 2-macroglobulin independently of the presence of heparin. On the basis of the reported kinetic data a lifespan of 420 s for plasmin, 66 s for miniplasmin and 4 s for PMN-elastase was calculated, when the enzymes are bound to fibrin in the presence of the four protease inhibitors at physiological plasma concentration. If heparin is present (300 nM) these values decrease to 240 s for plasmin and 42 s for miniplasmin, whereas that of PMN-elastase is unchanged. Thus, the present in vitro kinetic model suggests an antifibrinolytic effect of heparin in a plasma milieu.

Antifibrinolytic Agents↗
PubMed1988

Albendazole treatment of human cystic echinococcosis.

The effect of albendazole was investigated in 20 patients with single or multiorgan hydatid cyst disease. Albendazole was used at a dose of 10 mg/kg daily in cycles of 28 d for four cycles with 15 d between cycles. Follow-up ranged from 12-18 months. Response varied according to the organ involved, the most successful results being with liver and peritoneal cysts. A positive response was seen in 47% of 34 cyst sites and a partial response was seen in a further 38% of sites. Overall response was classed as completely successful in 30% of patients, and partially successful in 60% at the end of follow-up. Adverse events were rare, although occasional abnormalities of liver function were seen.

Adult↗
PubMed1987

Interaction of antithrombin III and thrombin-antithrombin III complex with cultured aortic endothelial cells.

The binding of antithrombin III, thrombin, thrombin-antithrombin III complex to endothelial cells was investigated. While the rate of the binding of thrombin to these cells was very rapid, that of antithrombin III was relatively slow and the thrombin-antithrombin III complex was intermediate. Binding kinetics indicated that antithrombin III, like thrombin, showed high affinity to endothelial cells; with a Kd of 3 X 10(-8) M and with 5 X 10(4) binding sites per cell. The dissociation of the inhibitor molecule was also rapid, i.e., approximately 70% bound antithrombin III was released in 2 minutes. Heparin, in a 100-fold molar excess to antithrombin III, or the modification of lysine residues of the inhibitor involved in the interaction with heparin, did not influence the association of antithrombin III with endothelial cells. In addition, antithrombin III did not compete with thrombin blocked in its active center for binding to endothelial cells. It is suggested that the binding sites of endothelial cells are different for thrombin and antithrombin III, and antithrombin III does not bind to these cells through its heparin binding domain.

Animals↗
PubMed1987

[Sensitivity of Salmonellae isolated from poultry to bacteriophage O1].

Studied were a total of 200 bacterial strains that agglutinated with the group B, C, D and E Salmonella sera. The organisms were isolated from viscera (liver, gallbladder, spleen, ovaries, and heart) and bone marrow from dead birds, from embryos, eggs, and washings from hatcheries, etc. in 1982-1985 in the district of Stara Zagora. It was found that the strains behaved biochemically as typical Salmonellae. Serologically typed of group B were 40 strains (S. typhimurium--34, and S. lagos--6); of group C--61 strains (S. oranienburg--38, S. isangi--7, S. montevideo--4, Salmonella II 6.7:gmst: 1.5--5, S. thompson--2, and S. newport--5); of group D--89 strains (S. gallinarum--57, S. gallinarum var. duisburg--23, S. pullorum--1, and S, enteritidis--8); and of group E--8 strains (S. senftenberg--4, S. anatum--4). Two of the strains were in the R form. Sensitive to the phage proved 89 +/- 5.7 per cent of the strains including the two R-form ones and those that were resistant of group C (S. oranienburg--5.4 per cent) and of group D (S. gallinarum--23 per cent, and S. gallinarum var. duisburg--26.1 per cent). The high sensitivity to the phage substantiated the phage identification of the strains as an adjunct, supplementary method in the complex diagnostics of diseases of a Salmonella etiology after the preliminarily determined phage for the respective region was made known.

Animals↗
PubMed1987

Unusual microscopic forms of experimental mesotheliomas.

A lightmicroscopic study is made on 36 pleural and 68 peritoneal experimental mesotheliomas induced in white rats by intrapleural and intraperitoneal introduction of asbestos dust. The experimental tumors were compared with 10 spontaneous human mesotheliomas (8 pleural and 2 peritoneal mesotheliomas). The analysis revealed 4 types of morphologically specific experimental mesotheliomas, which could not be referred to the classifications used. In this group are included: a) large cell alveolar, b) small cell alveolar; c) adenocystic; d) with squamous metaplasia and keratinization. The observed unusual experimental lightmicroscopic forms of mesotheliomas support the opinion for great plastic abilities of mesothelium, and the presence of squamous metaplasia with keratinization may be a reason for considering it as a variant of epithelium.

Animals↗
PubMed1986

[Etiology and chemotherapy of suppurative surgical infection in horses and cattle].

A total of 24 horses and 42 cattle with a variety of local suppurative processes (wounds, abscesses, phlegmons, tendovaginitis, etc.) were studied under conditions of the clinic with regard to the most commonly found microbial species and the opportunity to work out antibioticogrammes in terms of the effectiveness of 11 of the chemotherapeutic agents widely used in the practice. It was found that prevailing in horses were staphylococci and streptococci. In cattle Corynebacterium pyogenes was predominantly established. Besides, there was a rising trend in the part played by representative agents of the occasionally pathogenic microflora (Ps. aeruginosa, Pr. vulgaris, Escherichia coli) as the causative species of local suppurative processes. These organisms were fairly often isolated in association with other species, while they were more rarely found as the only acting ones in a particular case. Best effects of the antibiotics tested could be expectedly produced by gentamycin (82.5 per cent), carbenimycin (74.2 per cent), oxacyllin (72.7 per cent), ampicillin (68.2 per cent), and canamycin (61.8 per cent). At the same time, the effectiveness produced by some of the antibiotics widely employed in the practice, such as chloramphenicol, tetracycline, streptomycin, and penicillin was below 50 per cent.

Animals↗
PubMed1986

[Hygienic evaluation of the occupational risk in working with Bulgarian bentonite raw material].

The use of bentonite in various branches of industry, and first of all, in foundry workshops, grows rapidly. The literature data on health injuries by bentonite dust are rather contradictory: due primarily, to the changeable mineralogical composition of the raw material from different deposits. That requires a specific hygienic assessment of each deposit in exploitation. The authors studied the mineral composition, quantitative ratio of the mineral components and morphology of the particles from the respirable fraction of aerosol in the extraction of Bulgarian bentonite. The microscopic mineralogical analysis in phase contrast, established a basic mass of clay minerals, confirmed by the X-ray structural analysis. The free silicic oxide is presented by low-temperature crystobalite and quartz, more rarely opal and chalcedony. Its quantity does not surpass 1-2%. The experimental studies on experimental animals confirmed fibrosis, degree I and II, according to Belt and King. The clinical studies on the workers established the presence of reticular changes in the lungs, type S and L, according to ILO-UC classification. The hygienic characteristic of the Bulgarian bentonite provided grounds for its broad application as a substitute for more dangerous raw materials, quartz sand in the foundries, in particular. Regardless of its advantages, bentonite is not harmless. The adherence to MAC for dustiness and periodic control of the quartz content in the raw material and aerosol in the working environment, are compulsory.

Air Pollutants, Occupational↗
PubMed1985

[Ultrastructure of asbestos-induced mesotheliomas].

Experimental mesotheliomas induced in albino rats by treatment with isometric crocidolite asbestos were studied by light and electron microscopy. The cellular structure of different types of neoplasms was examined. The ultrastructural investigation was carried out using both freshly-resected materials and those recovered from paraffin blocks. The characteristic features of nuclei and cytoplasm are described with special attention being given to cytoplasmic organelles. On the basis of morphological light and electron microscopic study the authors discuss the histogenesis of different types of mesotheliomas. An attempt is being made to establish the origin of fibromatous mesotheliomas and to improve the available classifications.

Animals↗
PubMed1985

[Clinical, radiotelemetric and x-ray research on erythematous polyarthritis in lambs].

Experimental investigations were carried out with 6 lambs each infected i/v with 2 cm3 of a 24-hour broth culture of Erysipelothrix rhusiopathiae rated at 10(8) microbial cells per cu. cm. The clinical state of the animals was followed up in the course of 60 days, the changes in the cardiovascular system and those in the movements of the rumen being recorded radiotelemetrically, while the changes taking place in the joints were studied roentgenographically. It was found that the causative agent of swine erysipelas was strongly pathogenic for the lambs following a hematogenic infection, causing polyarthritis with concurrent changes in the general state--rise of temperature and higher respiration and pulse rates. The electrocardiograms of the affected animals showed sinus tachycardia, participation of Q waves, and changes in the R and T waves, while the graphic records of the rumen showed a drop in the number of rumen contractions and decrease in the amplitude. Roentgenographically, there were periostitis and osteoarthritis of the carpal and tarsal joints.

Animals↗
PubMed1983

[Pharmacological, toxicological, microbiological and pathohistological studies of gentamycin complex II].

The acute toxicity was determined of the gentamycin complex II (GMC-II) for albino mice, containing gentamycin components in a varying ratio. The LD50 at intraperitoneal application was 347.7 mg/kg body mass, while at oral application it was 5,180 mg (4933 divided by 5439) mg/kg body mass. Histopathologically, (mice killed with high doses of GMC-II, given orally) there were diffuse hyperemia of the liver, parenchymal degeneration of the kidney tubuli epithelium, and edema and emphysema of the lungs. The local tolerance with regard to a 5 per cent solution of GMC-II applied to the conjunctiva of rabbits at twofold treatment proved to be good. Determined were the minimal inhibiting concentrations of 14 species of pathogenic organisms of great interest to veterinary medicine (Bacillus anthracis, Erysipelothrix insidiosa, Salmonella gallinarum, Escherichia coli, etc.). The antibacterial spectrum of GMC-II was similar to that of gentamycin sulphate, however, for some pathogenic organisms higher concentrations were required to produce and antimicrobial effect. Similarly to gentamycin sulphate GMC-II had limited absorbtion in the alimentary canal of clinically normal newborn pigs and of birds. At a high rate (0.05 g/kg body mass) GMC-II applied via the crop to birds it was found to maintain the lowest therapeutic concentration in the serum. At the rate of 0.012 (equal to 12000 IU) per kg of body mass for 24 hours GMC-II produced therapeutic effects in newborn pigs affected with colibacteriosis.

Animals↗
PubMed1982

[Histochemical mechanisms in etiology of pulmonary fibrosis after short-term exposure to a mixture of dust and quartz from copper mine].

The authors induced pulmonary silicosis in albino rats by the intratracheal method with 50 mg mixed middling slime from Panaguiriste and quartz dust, dissolved in I ml physiological solution. The animals received a single treatment and were killed on 90th day of the experiment. Some intime characteristics of collagen-forming mechanisms in lungs were followed up via routine histological, histochemical, enzymohistochemical/ acid phosphatase activity, beta-glucoronidase, AS-esterase and lipase/ and autoradiographic/H3 labelled proline/ methods. It was established, that under the effect of both dusts from Panaguiriste mines studied/ mixed dust and pure quartz dust/ considerable deviations developed in the structure of the lungs of the experimental animals in the enzyme activity of acid phosphatase and carbon esterase, accompanied by various forms of fibrosis in the organ, depending on the dust applied. The difference in the composition of both dusts quartz and mixed dust slime - had an effect on the degree of the deviations, but not on their character, manifested in: I. specific protective reaction of organism, with activation of the ferments from the group of carbon esterase in macrophagic elements of interstitium and around the silicotic alterations in the lungs of the experimental animals; 2. inhibition of the maturation of macrophages in silicotic foci and 3. acceleration of the proliferation of fibroblasts with intensification of collagen-formation, accompanied by an enhanced activity of the ferments from the group of carbon esterase and in the cytoplasm of fibroblasts. The authors draw the conclusion that the complex use of routine histological, histochemical and quantitative isotope methods enables the more significant determination of fibrinogenicity of quartz-containing dust even at the early terms of their exposure under experimental conditions.

Acid Phosphatase↗
PubMed1981

[Creation of experimental emphysema by the intratracheal administration of papain].

The authors formed lung emphysema in white rats under experimental conditions by intratracheal application of various concentrations of papaine at different intervals. In the performed experiment the most suitable dose for formation of emphysema was two fold administration of 2 milligrams of papaine. The following indices were observed in the experimental and control animals: body weight, weight coefficient of the internal organs, indices of lipid and nucleinic metabolism in homogenates of lung as well as histomorphologic examination of lung.

Animals↗